C#DAL数据访问层

BaseDAL：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Reflection;

public class BaseDAL
{
    public static int Insert(ModelBase obj)
    {
        Type type = obj.GetType();  //获取类型

        object[] attr = type.GetCustomAttributes(typeof(MyKeyAttribute), false);    //获取自定义特性
        if (attr.Length == 0)
            throw new Exception("必须定义主键列");

        string Key = (attr[0] as MyKeyAttribute).Key;               //获取主键列
        bool IsIdentity = (attr[0] as MyKeyAttribute).IsIdentity;   //是否自增长

        StringBuilder sb1 = new StringBuilder();
        StringBuilder sb2 = new StringBuilder();
        List<SqlParameter> ps = new List<SqlParameter>();

        PropertyInfo[] infos = type.GetProperties();        //获取所有属性，即字段名，组装成sql语句
        foreach (PropertyInfo p in infos)
        {
            if (p.GetValue(obj, null) != null)
            {
                if (p.Name.ToLower() == Key.ToLower() && IsIdentity)    //如果是主键列且自增长就跳过
                    continue;

                sb1.Append(p.Name + ",");
                sb2.Append("@" + p.Name + ",");
                ps.Add(new SqlParameter("@" + p.Name, p.GetValue(obj, null)));
            }
        }

        string sql = string.Format("insert into {0}({1}) values({2})", type.Name, sb1.ToString().Trim(','), sb2.ToString().Trim(','));

        return DBHelper.CUD(sql, ps);
    }

    public static int InsertID(ModelBase obj)
    {
        Type type = obj.GetType();  //获取类型

        object[] attr = type.GetCustomAttributes(typeof(MyKeyAttribute), false);    //获取自定义特性
        if (attr.Length == 0)
            throw new Exception("必须定义主键列");

        string Key = (attr[0] as MyKeyAttribute).Key;               //获取主键列
        bool IsIdentity = (attr[0] as MyKeyAttribute).IsIdentity;   //是否自增长

        StringBuilder sb1 = new StringBuilder();
        StringBuilder sb2 = new StringBuilder();
        List<SqlParameter> ps = new List<SqlParameter>();

        PropertyInfo[] infos = type.GetProperties();        //获取所有属性，即字段名，组装成sql语句
        foreach (PropertyInfo p in infos)
        {
            if (p.GetValue(obj, null) != null)
            {
                if (p.Name.ToLower() == Key.ToLower() && IsIdentity)    //如果是主键列且自增长就跳过
                    continue;

                sb1.Append(p.Name + ",");
                sb2.Append("@" + p.Name + ",");
                ps.Add(new SqlParameter("@" + p.Name, p.GetValue(obj, null)));
            }
        }

        string sql = string.Format("insert into {0}({1}) values({2});select @@identity;", type.Name, sb1.ToString().Trim(','), sb2.ToString().Trim(','));

        return Convert.ToInt32(DBHelper.SelectObject(sql, ps));
    }

    public static int Update(ModelBase obj)
    {
        Type type = obj.GetType();  //获取类型

        object[] attr = type.GetCustomAttributes(typeof(MyKeyAttribute), false);    //通过自定义特性，获取主键列
        if (attr.Length == 0)
            throw new Exception("必须设定主键列！");

        string Key = (attr[0] as MyKeyAttribute).Key;
        object KeyValue = type.GetProperty(Key).GetValue(obj, null);    //获取主键列值
        if (KeyValue == null)
            throw new Exception("必须给主键列赋值！");

        StringBuilder sb1 = new StringBuilder();
        List<SqlParameter> ps = new List<SqlParameter>();

        PropertyInfo[] infos = type.GetProperties();        //获取所有列值，组装成sql语句
        foreach (PropertyInfo p in infos)
        {
            if (p.GetValue(obj, null) != null)
            {
                if (p.Name.ToLower() != Key.ToLower())
                {
                    sb1.Append(p.Name + "=@" + p.Name + ",");
                    ps.Add(new SqlParameter("@" + p.Name, p.GetValue(obj, null)));
                }
            }
        }

        string wstr = Key + "=@" + Key;             //获取主键列，组装成sql语句
        ps.Add(new SqlParameter("@" + Key, KeyValue));

        string sql = string.Format("update {0} set {1} where {2}", type.Name, sb1.ToString().Trim(','), wstr);

        return DBHelper.CUD(sql, ps);
    }

    public static int Delete<T>(object objID)
    {
        Type type = typeof(T);

        object[] attr = type.GetCustomAttributes(typeof(MyKeyAttribute), false);
        if (attr.Length == 0)
            throw new Exception("必须指定主键列！");

        string Key = (attr[0] as MyKeyAttribute).Key;
        string sql = string.Format("delete from {0} where {1}=@{1}", type.Name, Key);
        List<SqlParameter> ps = new List<SqlParameter>();
        ps.Add(new SqlParameter("@" + Key, objID));

        return DBHelper.CUD(sql, ps);
    }

    public static T SelectObj<T>(object objID)
    {
        Type type = typeof(T);

        object[] attr = type.GetCustomAttributes(typeof(MyKeyAttribute), false);
        if (attr.Length == 0)
            throw new Exception("必须设定主键列！");

        string Key = (attr[0] as MyKeyAttribute).Key;
        string sql = string.Format("select * from {0} where {1}=@{1}", type.Name, Key);
        List<SqlParameter> ps = new List<SqlParameter>();
        ps.Add(new SqlParameter("@" + Key, objID));

        T obj = Activator.CreateInstance<T>();
        using (DataTable dt = DBHelper.SelectTable(sql, ps))
        {
            for (int r = 0; r < dt.Rows.Count; r++)
            {
                PropertyInfo[] infos = type.GetProperties();
                foreach (PropertyInfo p in infos)
                {
                    for (int i = 0; i < dt.Columns.Count; i++)
                    {
                        if (p.Name.ToLower() == dt.Columns[i].ColumnName.ToLower())
                        {
                            if (dt.Rows[r][p.Name] != DBNull.Value)
                                p.SetValue(obj, dt.Rows[r][p.Name], null);
                        }
                    }
                }
            }
        }
        return obj;
    }

    public static List<T> SelectList<T>(string sql = null, List<SqlParameter> ps = null)
    {
        List<T> list = new List<T>();

        Type type = typeof(T);

        using (DataTable dt = (sql == null ? DBHelper.SelectTable("select * from " + type.Name) : DBHelper.SelectTable(sql, ps)))
        {
            for (int r = 0; r < dt.Rows.Count; r++)
            {
                T obj = Activator.CreateInstance<T>();
                PropertyInfo[] infos = type.GetProperties();

                foreach (PropertyInfo p in infos)
                {
                    for (int i = 0; i < dt.Columns.Count; i++)
                    {
                        if (p.Name.ToLower() == dt.Columns[i].ColumnName.ToLower())
                        {
                            if (dt.Rows[r][p.Name] != DBNull.Value)
                                p.SetValue(obj, dt.Rows[r][p.Name], null);
                        }
                    }
                }
                list.Add(obj);
            }
        }
        return list;
    }
}

EntityDAL:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;

public class EntityDAL : BaseDAL
{
　　//对表或视图实体的数据操作
}
            

ModelBase:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class ModelBase
{

}

Entity:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

[MyKey("ID",true)]
public class Entity : ModelBase
{
    public System.Int32 ID { get; set; }
    public System.String ClassName { get; set; }

    public Entity()
    {
        ClassName = string.Empty;
    }
}

MyKeyAttribute:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

//自定义特性类
public class MyKeyAttribute : Attribute
{
    public string Key { get; set; }         //主键列
    public bool IsIdentity { get; set; }    //是否自增长

    public MyKeyAttribute(string key, bool isIdentity)
    {
        this.Key = key;
        this.IsIdentity = isIdentity;
    }
}

DBHelper:

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public class DBHelper
{
    public static string connstr = ConfigurationManager.ConnectionStrings["connstr"].ToString();

    /// <summary>
    ///无参的增改删
    /// </summary>
    public static int CUD(string sql)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlCommand cmd = new SqlCommand(sql, conn);
            conn.Open();
            int result = cmd.ExecuteNonQuery();

            return result;
        }
    }
    

    /// <summary>
    ///有参的增改删
    /// </summary>
    public static int CUD(string sql, List<SqlParameter> ps)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlCommand cmd = new SqlCommand(sql, conn);
            if (ps != null)
                cmd.Parameters.AddRange(ps.ToArray());
            conn.Open();
            int result = cmd.ExecuteNonQuery();

            return result;
        }
    }

    /// <summary>
    ///无参、断开式数据操作
    /// </summary>
    public static DataSet SelectSet(string sql)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            DataSet ds = new DataSet();
            da.Fill(ds);
            return ds;
        }
    }


    /// <summary>
    ///无参、断开式数据操作
    /// </summary>
    public static DataTable SelectTable(string sql)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            DataSet ds = new DataSet();
            da.Fill(ds);

            return ds.Tables[0];
        }
    }

    /// <summary>
    ///有参、断开式数据操作
    /// </summary>
    
    public static DataTable SelectTable(string sql,List<SqlParameter> ps)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            if (ps != null)
                da.SelectCommand.Parameters.AddRange(ps.ToArray());
            DataSet ds = new DataSet();
            da.Fill(ds);

            return ds.Tables[0];
        }
    }

    /// <summary>
    ///无参、连接式数据操作
    /// </summary>
    
    public static SqlDataReader SelectReader(string sql)
    {
        SqlConnection conn = new SqlConnection(connstr);
        SqlCommand cmd = new SqlCommand(sql, conn);
        conn.Open();
        SqlDataReader sr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

        return sr;
    }

    /// <summary>
    ///有参、连接式数据操作
    /// </summary>
    
    public static SqlDataReader SelectReader(string sql,List<SqlParameter> ps)
    {
        SqlConnection conn = new SqlConnection(connstr);
        SqlCommand cmd = new SqlCommand(sql, conn);
        if (ps != null)
            cmd.Parameters.AddRange(ps.ToArray());
        conn.Open();
        SqlDataReader sr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

        return sr;
    }


    /// <summary>
    ///调用存储过程，返回DataSet
    /// </summary>
    
    public static DataSet SelectProc(string sql, List<SqlParameter> ps)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            //指定命令类型为存储过程模式
            da.SelectCommand.CommandType = CommandType.StoredProcedure;

            if (ps != null)
                da.SelectCommand.Parameters.AddRange(ps.ToArray());
            DataSet ds = new DataSet();
            da.Fill(ds);

            return ds;
        }
    }

    /// <summary>
    /// 调用存储过程，返回DataTable数组
    /// </summary>
    
    public static DataTable[] SelectProcTable(string sql, List<SqlParameter> ps)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            //指定命令类型为存储过程模式
            da.SelectCommand.CommandType = CommandType.StoredProcedure;

            if (ps != null)
                da.SelectCommand.Parameters.AddRange(ps.ToArray());
            DataSet ds = new DataSet();
            da.Fill(ds);

            DataTable[] dts = new DataTable[2];
            ds.Tables.CopyTo(dts, 0);

            return dts;
        }
    }


    /// <summary>
    /// 取单行单列的数据对象
    /// </summary>
    public static object SelectObject(string sql)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlCommand cmd = new SqlCommand(sql, conn);
            conn.Open();
            object obj = cmd.ExecuteScalar();
            //conn.Close();

            return obj;
        }
    }

    /// <summary>
    /// 取单行单列的数据对象
    /// </summary>
    public static object SelectObject(string sql, List<SqlParameter> ps)
    {
        using (SqlConnection conn = new SqlConnection(connstr))
        {
            SqlCommand cmd = new SqlCommand(sql, conn);
            conn.Open();
            if (ps != null)
                cmd.Parameters.AddRange(ps.ToArray());
            object obj = cmd.ExecuteScalar();
            //conn.Close();

            return obj;
        }
    }
}