public static OleDbDataReader Executereader1(string strSQL)
{
OleDbConnection myconn = new OleDbConnection(conn);
OleDbCommand mycmd = new OleDbCommand(strSQL,myconn);
try
{
myconn.Open();
OleDbDataReader myreader = mycmd.ExecuteReader();
//return myreader;
return myreader; }
catch(Exception e)
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return myreader; }
finally
{
myconn.Close();
} }
错误信息,D:\产品\product manage\product manage\sql.cs(65): 名称“myreader”在类或命名空间“SqlLib.SqlHelper”中不存在
{
OleDbConnection myconn = new OleDbConnection(conn);
OleDbCommand mycmd = new OleDbCommand(strSQL,myconn);
try
{
myconn.Open();
OleDbDataReader myreader = mycmd.ExecuteReader();
//return myreader;
return myreader; }
catch(Exception e)
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return myreader; }
finally
{
myconn.Close();
} }
错误信息,D:\产品\product manage\product manage\sql.cs(65): 名称“myreader”在类或命名空间“SqlLib.SqlHelper”中不存在
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return NULL; //myreader没在这个域内声明的。 }
取不到数据, 返回datareader也没用啊。
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{
OleDbConnection myconn = new OleDbConnection(conn);
OleDbCommand mycmd = new OleDbCommand(strSQL,myconn);
OleDbDataReader myreader = new OleDbDataReader();
try
{
myconn.Open();
myreader = mycmd.ExecuteReader();
//return myreader;
return myreader; }
catch(Exception e)
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return myreader; }
finally
{
myconn.Close();
}
}
{ OleDbConnection myconn = new OleDbConnection(conn);
OleDbCommand mycmd = new OleDbCommand(strSQL,myconn);
OleDbDataReader myreader = new OleDbDataReader();
try
{
myconn.Open();
myreader = mycmd.ExecuteReader();
return myreader;
}
catch(Exception e)
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return myreader;
}
finally
{
myconn.Close();
} }
新代码
public static OleDbDataReader Executereader1(string strSQL)
{
OleDbConnection myconn = new OleDbConnection(conn);
OleDbCommand mycmd = new OleDbCommand(strSQL,myconn);
try
{
myconn.Open();
OleDbDataReader myreader = mycmd.ExecuteReader();
return myreader;
}
catch(Exception e)
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return;//这里不能用 return myreader;像3楼说的
}
finally
{
myconn.Close();
} }
{ OleDbConnection myconn = new OleDbConnection("");
OleDbCommand mycmd = new OleDbCommand(strSQL, myconn);
OleDbDataReader myreader = null;
try
{
myconn.Open();
myreader = mycmd.ExecuteReader();
return myreader;
}
catch (Exception e)
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return myreader;
} finally
{
myconn.Close();
}
}
如:OleDbDataReader myreader = Executereader1("");
if(myreader == null)
{
return;
}
public static OleDbDataReader Executereader1(string strSQL)
{
OleDbConnection myconn = new OleDbConnection(conn);
OleDbCommand mycmd = new OleDbCommand(strSQL,myconn);
try
{
myconn.Open();
System.Data.OleDb.OleDbDataReader myreader = mycmd.ExecuteReader();
return myreader;
}
catch(Exception e)
{
MessageBox.Show("数据库执行异常,出现的错误原因是:" + e.ToString());
return null;//这里不能用 return myreader;像3楼说的
}
finally
{
myconn.Close();
} }或者你调试跟进去看看,myreader = mycmd.ExecuteReader();有值没有?
还有 为什么要static 呢