在asp.net中使用公共类可以节省很多代码，DBHelp这个类我们经常用，现在来简单介绍一下：
连接字符串从配置文件中读取
private readonly static string CONNSTRING = ConfigurationManager.ConnectionStrings["ConnString"].ConnectionString;
执行增删改操作方法
public static void GetExecuteNonQuery(string sqlstr,params SqlParameter[] paras)
{
using(SqlConnection conn=new SqlConnection(CONNSTRING))
{
try{
SqlCommand cmd = new SqlCommand(sqlstr,conn);
cmd.Parameters.AddRange(paras);
conn.Open();
cmd.ExecuteNonQuery();
}catch(OleDbException e){
throw new Exception(e.Message);
}
}
}
执行检索查询方法
public static SqlDataReader GetReader(string sqlstr, params SqlParameter[] paras)
{
try{
SqlConnection conn = new SqlConnection(CONNSTRING);
SqlCommand cmd = new SqlCommand(sqlstr, conn);
cmd.Parameters.AddRange(paras);
conn.Open();
return cmd.ExecuteReader(CommandBehavior.CloseConnection);
}catch(OleDbException e){
throw new Exception(e.Message);
}
}
注：CommandBehavior.CloseConnection表示关闭SqlDataReader的同时把连接也关掉
返回第一行第一列的方法
public static object GetExecuteScalar(string sqlstr, params SqlParameter[] paras)
{
using (SqlConnection conn = new SqlConnection(CONNSTRING))
{
try
{
SqlCommand cmd = new SqlCommand(sqlstr, conn);
cmd.Parameters.AddRange(paras);
conn.Open();
return cmd.ExecuteScalar();
} catch(OleDbException e){
throw new Exception(e.Message);
}
}
}
返回DataTable对象
public static DataTable GetDataSet(string sql, SqlParameter[] paramters)
{
using (SqlConnection conn = new SqlConnection(CONNSTRING))
{
try{
DataSet ds = new DataSet();
SqlCommand command = new SqlCommand(sql, conn);
command.Parameters.AddRange(paramters);
SqlDataAdapter adapter = new SqlDataAdapter(command);
adapter.Fill(ds);
return ds.Tables[0];
}catch(OleDbException e){
throw new Exception(e.Message);
}
}
}
返回DataSet
public static DataSet Query(string sqlstr, params OleDbParameter[] paras)
{
using(OleDbConnection conn=new OleDbConnection(CONNSTR))
{
try
{
DataSet ds = new DataSet();
OleDbCommand cmd = new OleDbCommand(sqlstr, conn);
cmd.Parameters.AddRange(paras);
OleDbDataAdapter da = new OleDbDataAdapter();
da.SelectCommand = cmd;
da.Fill(ds, "ds");
return ds;
}
catch (OleDbException e)
{
throw new Exception(e.Message);
}
}
}
public static DataSet Query(string sqlstr)
{
using(OleDbConnection conn=new OleDbConnection(CONNSTR))
{
try
{
DataSet ds = new DataSet();
OleDbCommand cmd = new OleDbCommand(sqlstr, conn);
OleDbDataAdapter da = new OleDbDataAdapter();
da.Fill(ds, "ds");
return ds;
}
catch (OleDbException e)
{
throw new Exception(e.Message);
}
}
}
执行多条SQL语句，实现数据库事务
public static void ExecuteSqlTran(ArrayList SQLStringList)
{
int fig=0;//用来判断是否执行成功
using (OleDbConnection conn = new OleDbConnection(CONNSTR))
{
conn.Open();
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = conn;
OleDbTransaction 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;
if(cmd.ExecuteNonQuery()>0)
{
fig++;
}
}
}
tx.Commit();
}
catch (System.Data.OleDb.OleDbException E)
{
fig=-1;
tx.Rollback();
throw new Exception(E.Message);
}
}
}
其中SqlParameter[] paramters在返回范性集合的时候可以写参数或者没有参数也可以不写，但是返回dataTable或者DataSet的时候要写！
获得新增数据的id(access)
public void ExecuteSql(string cmdText, IDataParameter[] cmdParameters, out DataTable dt)
{
try
{
this._DbCommand.CommandText = cmdText;
foreach (IDataParameter parameter in cmdParameters)
{
this._DbCommand.Parameters.Add(parameter);
}
this._DbDataAdapter.SelectCommand = this._DbCommand;
DataSet dataSet = new DataSet();
this._DbDataAdapter.Fill(dataSet);
dt = dataSet.Tables[0];
}
catch (Exception exception)
{
this.CloseConnection();
throw new Exception(exception.Message);
}
}