防止连接泄漏的两种SQLHelper.cs文件写法

下面的两个类，对SQL的连接对象进行了严格的控制，可以有效的防止连接的 泄漏

第一种：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Data;
using System.Text;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;
using System.Xml;
using System.Reflection;

namespace BaseClass
{
    public class SqlHelper2
    {
        protected static string connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
        #region  执行简单SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand(SQLString, conn))
                {
                    try
                    {
                        conn.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SqlClient.SqlException E)
                    {

                        throw new Exception(E.Message);
                    }
                    finally
                    {
                        conn.Close();
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param> 
        public static void ExecuteSqlTran(ArrayList SQLStringList)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = conn;
                SqlTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    for (int n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n].ToString();
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    tx.Rollback();
                    throw new Exception(E.Message);
                }
                finally
                {
                    conn.Close();
                }
            }
        }
        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, string content)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand(SQLString, connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content", SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        /// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand(strSQL, connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@fs", SqlDbType.Image);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SqlClient.SqlException e)
                    {

                        throw new Exception(e.Message);
                    }
                    finally
                    {
                        connection.Close();
                    }
                }
            }
        }
        /// <summary>
        /// 执行查询语句，返回SqlDataReader(此方法不能用，没有关闭连接)（因为SqlConnection对象是在方法内定义的，外部无法关闭）
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string strSQL)
        {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand(strSQL, connection);
            try
            {
                connection.Open();
                SqlDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
                throw new Exception(e.Message);
            }

        }
        /// <summary>
        /// 从上面的ExecuteReader不能用，改成下面的方法，但打开连接是从此方法中进行，要从此方法外（调用处）关闭连接(我自己写的方法)
        /// </summary>
        /// <param name="strSQL"></param>
        /// <param name="conn"></param>
        /// <returns></returns>
        public static SqlDataReader ExecuteReader(string strSQL, SqlConnection conn)
        {
            // SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand(strSQL, conn);
            try
            {
                conn.Open();
                SqlDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
                throw new Exception(e.Message);
            }

        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    if (connection.State ==ConnectionState.Open)
                        connection.Close();
                    SqlDataAdapter command = new SqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SqlClient.SqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                finally
                {
                   // connection.Close();

                }
                return ds;
            }
        }

        #endregion

        #region 执行带参数的SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, params SqlParameter[] cmdParms)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (System.Data.SqlClient.SqlException E)
                    {
                        throw new Exception(E.Message);
                    }
                    finally
                    {
                        connection.Close();
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SqlParameter[]）</param>
        public static void ExecuteSqlTran(Hashtable SQLStringList)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                conn.Open();
                using (SqlTransaction trans = conn.BeginTransaction())
                {
                    SqlCommand cmd = new SqlCommand();
                    try
                    {
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            SqlParameter[] cmdParms = (SqlParameter[])myDE.Value;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();

                            trans.Commit();
                        }
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                    finally
                    {
                        conn.Close();
                    }
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString, params SqlParameter[] cmdParms)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SqlClient.SqlException e)
                    {
                        throw new Exception(e.Message);
                    }
                    finally
                    {
                        connection.Close();

                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，返回SqlDataReader(此方法不能用，没有关闭连接)
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string SQLString, params SqlParameter[] cmdParms)
        {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand();
            try
            {
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                connection.Open();//连接没有关闭
                SqlDataReader myReader = cmd.ExecuteReader();
                cmd.Parameters.Clear();
                return myReader;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
                throw new Exception(e.Message);
            }

        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString, params SqlParameter[] cmdParms)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        if (connection.State == ConnectionState.Open)
                        {
                            connection.Close();
                        }
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (System.Data.SqlClient.SqlException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    return ds;
                }
            }
        }
      

        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, string cmdText, SqlParameter[] cmdParms)
        {
            //if (conn.State != ConnectionState.Open)
            //    conn.Open();//??
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;

            if (cmdParms != null)
            {
                foreach (SqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        #endregion

        #region 存储过程操作

        /// <summary>
        /// 执行存储过程(此方法不能用，没有关闭连接)
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters)
        {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlDataReader returnReader;
            connection.Open();
            SqlCommand command = BuildQueryCommand(connection, storedProcName, parameters);
            command.CommandType = CommandType.StoredProcedure;
            returnReader = command.ExecuteReader();
            return returnReader;
        }

        /// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <param name="tableName">DataSet结果中的表名</param>
        /// <returns>DataSet</returns>
        public static DataSet RunProcedure(string storedProcName, IDataParameter[] parameters, string tableName)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet dataSet = new DataSet();
                connection.Open();
                SqlDataAdapter sqlDA = new SqlDataAdapter();
                sqlDA.SelectCommand = BuildQueryCommand(connection, storedProcName, parameters);
                sqlDA.Fill(dataSet, tableName);
                connection.Close();
                return dataSet;
            }
        }

        /// <summary>
        /// 构建 SqlCommand 对象(用来返回一个结果集，而不是一个整数值)
        /// </summary>
        /// <param name="connection">数据库连接</param>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlCommand</returns>
        private static SqlCommand BuildQueryCommand(SqlConnection connection, string storedProcName, IDataParameter[] parameters)
        {
            SqlCommand command = new SqlCommand(storedProcName, connection);
            command.CommandType = CommandType.StoredProcedure;
            foreach (SqlParameter parameter in parameters)
            {
                command.Parameters.Add(parameter);
            }
            return command;
        }

        /// <summary>
        /// 执行存储过程，返回影响的行数 
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <param name="rowsAffected">影响的行数</param>
        /// <returns></returns>
        public static int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                int result;
                connection.Open();
                SqlCommand command = BuildIntCommand(connection, storedProcName, parameters);
                rowsAffected = command.ExecuteNonQuery();
                result = (int)command.Parameters["ReturnValue"].Value;
                connection.Close();
                return result;
            }
        }

        /// <summary>
        /// 创建 SqlCommand 对象实例(用来返回一个整数值)
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlCommand 对象实例</returns>
        private static SqlCommand BuildIntCommand(SqlConnection connection, string storedProcName, IDataParameter[] parameters)
        {
            SqlCommand command = BuildQueryCommand(connection, storedProcName, parameters);
            command.Parameters.Add(new SqlParameter("ReturnValue",
                SqlDbType.Int, 4, ParameterDirection.ReturnValue,
                false, 0, 0, string.Empty, DataRowVersion.Default, null));
            return command;
        }
        #endregion
        #region 由Object取值
        /// <summary>
        /// 取得Int值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>int值</returns>
        public static int GetInt(object obj)
        {
            if (obj.ToString() != "")
                return int.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 取得byte值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>byte值</returns>
        public static byte Getbyte(object obj)
        {
            if (obj.ToString() != "")
                return byte.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 获得Long值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>long值</returns>
        public static long GetLong(object obj)
        {
            if (obj.ToString() != "")
                return long.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 取得Decimal值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>decimal值</returns>
        public static decimal GetDecimal(object obj)
        {
            if (obj.ToString() != "")
                return decimal.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 取得Guid值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>Guid值</returns>
        public static Guid GetGuid(object obj)
        {
            if (obj.ToString() != "")
                return new Guid(obj.ToString());
            else
                return Guid.Empty;
        }

        /// <summary>
        /// 取得DateTime值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>DateTime值</returns>
        public static DateTime GetDateTime(object obj)
        {
            if (obj.ToString() != "")
                return DateTime.Parse(obj.ToString());
            else
                return DateTime.MinValue;
        }

        /// <summary>
        /// 取得bool值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>bool值</returns>
        public static bool GetBool(object obj)
        {
            if (obj.ToString() == "1" || obj.ToString().ToLower() == "true")
                return true;
            else
                return false;
        }

        /// <summary>
        /// 取得byte[]值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>byte[]值</returns>
        public static Byte[] GetByte(object obj)
        {
            if (obj.ToString() != "")
            {
                return (Byte[])obj;
            }
            else
                return null;
        }

        /// <summary>
        /// 取得string值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>string值</returns>
        public static string GetString(object obj)
        {
            return obj.ToString();
        }
        #endregion
        #region 序列化与反序列化
        /// <summary>
        /// 序列化对象
        /// </summary>
        /// <param name="obj">要序列化的对象</param>
        /// <returns>返回二进制</returns>
        public static byte[] SerializeModel(Object obj)
        {
            if (obj != null)
            {
                BinaryFormatter binaryFormatter = new BinaryFormatter();
                MemoryStream ms = new MemoryStream();
                byte[] b;
                binaryFormatter.Serialize(ms, obj);
                ms.Position = 0;
                b = new Byte[ms.Length];
                ms.Read(b, 0, b.Length);
                ms.Close();
                return b;
            }
            else
                return new byte[0];
        }

        /// <summary>
        /// 反序列化对象
        /// </summary>
        /// <param name="b">要反序列化的二进制</param>
        /// <param name="SampleModel">Model的实体示例，New一个出来即可</param>
        /// <returns>返回对象</returns>
        public static object DeserializeModel(byte[] b, object SampleModel)
        {
            if (b == null || b.Length == 0)
                return SampleModel;
            else
            {
                object result = new object();
                BinaryFormatter binaryFormatter = new BinaryFormatter();
                MemoryStream ms = new MemoryStream();
                try
                {
                    ms.Write(b, 0, b.Length);
                    ms.Position = 0;
                    result = binaryFormatter.Deserialize(ms);
                    ms.Close();
                }
                catch { }
                return result;
            }
        }
        #endregion

        #region Model与XML互相转换
        /// <summary>
        /// Model转化为XML的方法
        /// </summary>
        /// <param name="model">要转化的Model</param>
        /// <returns></returns>
        public static string ModelToXML(object model)
        {
            XmlDocument xmldoc = new XmlDocument();
            XmlElement ModelNode = xmldoc.CreateElement("Model");
            xmldoc.AppendChild(ModelNode);

            if (model != null)
            {
                foreach (PropertyInfo property in model.GetType().GetProperties())
                {
                    XmlElement attribute = xmldoc.CreateElement(property.Name);
                    if (property.GetValue(model, null) != null)
                        attribute.InnerText = property.GetValue(model, null).ToString();
                    else
                        attribute.InnerText = "[Null]";
                    ModelNode.AppendChild(attribute);
                }
            }

            return xmldoc.OuterXml;
        }

        /// <summary>
        /// XML转化为Model的方法
        /// </summary>
        /// <param name="xml">要转化的XML</param>
        /// <param name="SampleModel">Model的实体示例，New一个出来即可</param>
        /// <returns></returns>
        public static object XMLToModel(string xml, object SampleModel)
        {
            if (string.IsNullOrEmpty(xml))
                return SampleModel;
            else
            {
                XmlDocument xmldoc = new XmlDocument();
                xmldoc.LoadXml(xml);

                XmlNodeList attributes = xmldoc.SelectSingleNode("Model").ChildNodes;
                foreach (XmlNode node in attributes)
                {
                    foreach (PropertyInfo property in SampleModel.GetType().GetProperties())
                    {
                        if (node.Name == property.Name)
                        {
                            if (node.InnerText != "[Null]")
                            {
                                if (property.PropertyType == typeof(System.Guid))
                                    property.SetValue(SampleModel, new Guid(node.InnerText), null);
                                else
                                    property.SetValue(SampleModel, Convert.ChangeType(node.InnerText, property.PropertyType), null);
                            }
                            else
                                property.SetValue(SampleModel, null, null);
                        }
                    }
                }
                return SampleModel;
            }
        }
        #endregion
    }
}

第二种：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Data;
using System.Text;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;
using System.Xml;
using System.Reflection;

namespace BaseClass
{
    public class SqlHelper
    {
        protected static string connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
        private static SqlConnection conn = new SqlConnection(connectionString);

        #region  执行简单SQL语句

        public void connOpen()
        {
            if(conn.State==ConnectionState.Closed)
            {
            conn.Open();
            }
        }

        public void connClose()
        {
            if(conn.State==ConnectionState.Open)
            {
            conn.Close();
            }
        }

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
           
                using (SqlCommand cmd = new SqlCommand(SQLString, conn))
                {
                    try
                    {
                        conn.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SqlClient.SqlException E)
                    {

                        throw new Exception(E.Message);
                    }
                    finally
                    {
                        conn.Close();
                    }
                }
           
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param> 
        public static void ExecuteSqlTran(ArrayList SQLStringList)
        {
          
                conn.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = conn;
                SqlTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    for (int n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n].ToString();
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    tx.Rollback();
                    throw new Exception(E.Message);
                }
                finally
                {
                    conn.Close();
                }
           
        }
        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, string content)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                SqlCommand cmd = new SqlCommand(SQLString, conn);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content", SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    conn.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    conn.Close();
                }
           
        }
        /// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                SqlCommand cmd = new SqlCommand(strSQL, conn);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@fs", SqlDbType.Image);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    conn.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    conn.Close();
                }
            //}
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                using (SqlCommand cmd = new SqlCommand(SQLString, conn))
                {
                    try
                    {
                        conn.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SqlClient.SqlException e)
                    {
                       
                        throw new Exception(e.Message);
                    }
                    finally
                    {
                        conn.Close();
                    }
                }
            //}
        }
        /// <summary>
        /// 执行查询语句，返回SqlDataReader(此方法不能用，没有关闭连接)
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string strSQL)
        {
            //SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand(strSQL, conn);
            try
            {
                conn.Open();
                SqlDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
                throw new Exception(e.Message);
            }

        }
        /// <summary>
        /// 从上面的ExecuteReader不能用，改成下面的方法，但打开连接是从此方法中进行，要从此方法外（调用处）关闭连接(我自己写的方法)
        /// </summary>
        /// <param name="strSQL"></param>
        /// <param name="conn"></param>
        /// <returns></returns>
        public static SqlDataReader ExecuteReader(string strSQL,SqlConnection conn)
        {
           // SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand(strSQL, conn);
            try
            {
                conn.Open();
                SqlDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
                throw new Exception(e.Message);
            }

        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                DataSet ds = new DataSet();
                try
                {
                    conn.Open();
                    SqlDataAdapter command = new SqlDataAdapter(SQLString, conn);
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SqlClient.SqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                finally
                {
                    conn.Close();
               
                }
                return ds;
            //}
        }

        #endregion

        #region 执行带参数的SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, params SqlParameter[] cmdParms)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, conn, null, SQLString, cmdParms);
                        conn.Open();
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (System.Data.SqlClient.SqlException E)
                    {
                        throw new Exception(E.Message);
                    }
                    finally
                    {
                        conn.Close();
                    }
                }
           // }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SqlParameter[]）</param>
        public static void ExecuteSqlTran(Hashtable SQLStringList)
        {
            //using (SqlConnection conn = new SqlConnection(connectionString))
            //{
                conn.Open();
                using (SqlTransaction trans = conn.BeginTransaction())
                {
                    SqlCommand cmd = new SqlCommand();
                    try
                    {
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            SqlParameter[] cmdParms = (SqlParameter[])myDE.Value;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();

                            trans.Commit();
                        }
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                    finally
                    {
                        conn.Close();
                    }
                }
           // }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString, params SqlParameter[] cmdParms)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, conn, null, SQLString, cmdParms);
                        conn.Open();
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SqlClient.SqlException e)
                    {
                        throw new Exception(e.Message);
                    }
                    finally
                    {
                        conn.Close();
                   
                    }
               // }
            }
        }

        /// <summary>
        /// 执行查询语句，返回SqlDataReader(此方法不能用，没有关闭连接),  可以采用下面的方法，转成dt返回。
        /////  if (myReader.HasRows)
        //        {
        //            dt.Load(SqlDr);//读取SqlDataReader里的内容
        //        }
        //        this.dataGridView1.DataSource = dt;

        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string SQLString, params SqlParameter[] cmdParms)
        {
           // SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand();
            try
            {
                PrepareCommand(cmd, conn, null, SQLString, cmdParms);
                conn.Open();//连接没有关闭
                SqlDataReader myReader = cmd.ExecuteReader();
                cmd.Parameters.Clear();
                return myReader;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
                throw new Exception(e.Message);
            }

        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString, params SqlParameter[] cmdParms)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, conn, null, SQLString, cmdParms);
                using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        if (conn.State == ConnectionState.Open)
                        {
                            conn.Close();
                        }
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (System.Data.SqlClient.SqlException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    finally
                    {
                        conn.Close();
                    }
                    return ds;
                }
           // }
        }

        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, string cmdText, SqlParameter[] cmdParms)
        {
            //if (conn.State != ConnectionState.Open)
            //    conn.Open();//??
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;

            if (cmdParms != null)
            {
                foreach (SqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        #endregion

        #region 存储过程操作

        /// <summary>
        /// 执行存储过程(此方法不能用，没有关闭连接)
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters)
        {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlDataReader returnReader;
            connection.Open();
            SqlCommand command = BuildQueryCommand(connection, storedProcName, parameters);
            command.CommandType = CommandType.StoredProcedure;
            returnReader = command.ExecuteReader();
            return returnReader;
        }

        /// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <param name="tableName">DataSet结果中的表名</param>
        /// <returns>DataSet</returns>
        public static DataSet RunProcedure(string storedProcName, IDataParameter[] parameters, string tableName)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet dataSet = new DataSet();
                connection.Close();
                SqlDataAdapter sqlDA = new SqlDataAdapter();
                sqlDA.SelectCommand = BuildQueryCommand(connection, storedProcName, parameters);
                sqlDA.Fill(dataSet, tableName);
                connection.Close();
                return dataSet;
            }
        }

        /// <summary>
        /// 构建 SqlCommand 对象(用来返回一个结果集，而不是一个整数值)
        /// </summary>
        /// <param name="connection">数据库连接</param>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlCommand</returns>
        private static SqlCommand BuildQueryCommand(SqlConnection connection, string storedProcName, IDataParameter[] parameters)
        {
            SqlCommand command = new SqlCommand(storedProcName, connection);
            command.CommandType = CommandType.StoredProcedure;
            foreach (SqlParameter parameter in parameters)
            {
                command.Parameters.Add(parameter);
            }
            return command;
        }

        /// <summary>
        /// 执行存储过程，返回影响的行数 
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <param name="rowsAffected">影响的行数</param>
        /// <returns></returns>
        public static int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected)
        {
            //using (SqlConnection connection = new SqlConnection(connectionString))
            //{
                int result;
                conn.Open();
                SqlCommand command = BuildIntCommand(conn, storedProcName, parameters);
                rowsAffected = command.ExecuteNonQuery();
                result = (int)command.Parameters["ReturnValue"].Value;
                conn.Close();
                return result;
          //  }
        }

        /// <summary>
        /// 创建 SqlCommand 对象实例(用来返回一个整数值)
        /// </summary>
        /// <param name="storedProcName">存储过程名</param>
        /// <param name="parameters">存储过程参数</param>
        /// <returns>SqlCommand 对象实例</returns>
        private static SqlCommand BuildIntCommand(SqlConnection connection, string storedProcName, IDataParameter[] parameters)
        {
            SqlCommand command = BuildQueryCommand(connection, storedProcName, parameters);
            command.Parameters.Add(new SqlParameter("ReturnValue",
                SqlDbType.Int, 4, ParameterDirection.ReturnValue,
                false, 0, 0, string.Empty, DataRowVersion.Default, null));
            return command

       }
        #endregion
        #region 由Object取值
        /// <summary>
        /// 取得Int值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>int值</returns>
        public static int GetInt(object obj)
        {
            if (obj.ToString() != "")
                return int.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 取得byte值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>byte值</returns>
        public static byte Getbyte(object obj)
        {
            if (obj.ToString() != "")
                return byte.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 获得Long值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>long值</returns>
        public static long GetLong(object obj)
        {
            if (obj.ToString() != "")
                return long.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 取得Decimal值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>decimal值</returns>
        public static decimal GetDecimal(object obj)
        {
            if (obj.ToString() != "")
                return decimal.Parse(obj.ToString());
            else
                return 0;
        }

        /// <summary>
        /// 取得Guid值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>Guid值</returns>
        public static Guid GetGuid(object obj)
        {
            if (obj.ToString() != "")
                return new Guid(obj.ToString());
            else
                return Guid.Empty;
        }

        /// <summary>
        /// 取得DateTime值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>DateTime值</returns>
        public static DateTime GetDateTime(object obj)
        {
            if (obj.ToString() != "")
                return DateTime.Parse(obj.ToString());
            else
                return DateTime.MinValue;
        }

        /// <summary>
        /// 取得bool值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>bool值</returns>
        public static bool GetBool(object obj)
        {
            if (obj.ToString() == "1" || obj.ToString().ToLower() == "true")
                return true;
            else
                return false;
        }

        /// <summary>
        /// 取得byte[]值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>byte[]值</returns>
        public static Byte[] GetByte(object obj)
        {
            if (obj.ToString() != "")
            {
                return (Byte[])obj;
            }
            else
                return null;
        }

        /// <summary>
        /// 取得string值
        /// </summary>
        /// <param name="obj">object对象</param>
        /// <returns>string值</returns>
        public static string GetString(object obj)
        {
            return obj.ToString();
        }
        #endregion
        #region 序列化与反序列化
        /// <summary>
        /// 序列化对象
        /// </summary>
        /// <param name="obj">要序列化的对象</param>
        /// <returns>返回二进制</returns>
        public static byte[] SerializeModel(Object obj)
        {
            if (obj != null)
            {
                BinaryFormatter binaryFormatter = new BinaryFormatter();
                MemoryStream ms = new MemoryStream();
                byte[] b;
                binaryFormatter.Serialize(ms, obj);
                ms.Position = 0;
                b = new Byte[ms.Length];
                ms.Read(b, 0, b.Length);
                ms.Close();
                return b;
            }
            else
                return new byte[0];
        }

        /// <summary>
        /// 反序列化对象
        /// </summary>
        /// <param name="b">要反序列化的二进制</param>
        /// <param name="SampleModel">Model的实体示例，New一个出来即可</param>
        /// <returns>返回对象</returns>
        public static object DeserializeModel(byte[] b, object SampleModel)
        {
            if (b == null || b.Length == 0)
                return SampleModel;
            else
            {
                object result = new object();
                BinaryFormatter binaryFormatter = new BinaryFormatter();
                MemoryStream ms = new MemoryStream();
                try
                {
                    ms.Write(b, 0, b.Length);
                    ms.Position = 0;
                    result = binaryFormatter.Deserialize(ms);
                    ms.Close();
                }
                catch { }
                return result;
            }
        }
        #endregion

        #region Model与XML互相转换
        /// <summary>
        /// Model转化为XML的方法
        /// </summary>
        /// <param name="model">要转化的Model</param>
        /// <returns></returns>
        public static string ModelToXML(object model)
        {
            XmlDocument xmldoc = new XmlDocument();
            XmlElement ModelNode = xmldoc.CreateElement("Model");
            xmldoc.AppendChild(ModelNode);

            if (model != null)
            {
                foreach (PropertyInfo property in model.GetType().GetProperties())
                {
                    XmlElement attribute = xmldoc.CreateElement(property.Name);
                    if (property.GetValue(model, null) != null)
                        attribute.InnerText = property.GetValue(model, null).ToString();
                    else
                        attribute.InnerText = "[Null]";
                    ModelNode.AppendChild(attribute);
                }
            }

            return xmldoc.OuterXml;
        }

        /// <summary>
        /// XML转化为Model的方法
        /// </summary>
        /// <param name="xml">要转化的XML</param>
        /// <param name="SampleModel">Model的实体示例，New一个出来即可</param>
        /// <returns></returns>
        public static object XMLToModel(string xml, object SampleModel)
        {
            if (string.IsNullOrEmpty(xml))
                return SampleModel;
            else
            {
                XmlDocument xmldoc = new XmlDocument();
                xmldoc.LoadXml(xml);

                XmlNodeList attributes = xmldoc.SelectSingleNode("Model").ChildNodes;
                foreach (XmlNode node in attributes)
                {
                    foreach (PropertyInfo property in SampleModel.GetType().GetProperties())
                    {
                        if (node.Name == property.Name)
                        {
                            if (node.InnerText != "[Null]")
                            {
                                if (property.PropertyType == typeof(System.Guid))
                                    property.SetValue(SampleModel, new Guid(node.InnerText), null);
                                else
                                    property.SetValue(SampleModel, Convert.ChangeType(node.InnerText, property.PropertyType), null);
                            }
                            else
                                property.SetValue(SampleModel, null, null);
                        }
                    }
                }
                return SampleModel;
            }
        }
        #endregion
    }
}

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