Table To Table

 

            OleDbConnection conn  =   new  OleDbConnection();
            DataTable mydt  =   new  DataTable( " mydt " );
            DataColumn dc  =   new  DataColumn();
            dc.DataType  =  System.Type.GetType( " System.String " );
            dc.ColumnName  =   " id " ;
             // dc.DefaultValue = "11";
            mydt.Columns.Add( " id " );

            dc.DataType  =  System.Type.GetType( " System.String " );
            dc.ColumnName  =   " name " ;
             // dc.DefaultValue = "myname";
            mydt.Columns.Add( " name " );

            dc.DataType  =  System.Type.GetType( " System.String " );
            dc.ColumnName  =   " pwd " ;
             // dc.DefaultValue = "mypwd";
            mydt.Columns.Add( " pwd " );

            DataRow dr  =   null ;
            dr  =  mydt.NewRow();
            dr[ " id " ]  =   " 11 " ;
            dr[ " name " ]  =   " myname11 " ;
            dr[ " pwd " ]  =   " mypwd11 " ;
            mydt.Rows.Add(dr);

            dr  =  mydt.NewRow();
            dr[ " id " ]  =   " 22 " ;
            dr[ " name " ]  =   " myname22 " ;
            dr[ " pwd " ]  =   " mypwd22 " ;
            mydt.Rows.Add(dr);

            dr  =  mydt.NewRow();
            dr[ " id " ]  =   " 33 " ;
            dr[ " name " ]  =   " myname33 " ;
            dr[ " pwd " ]  =   " mypwd33 " ;
            mydt.Rows.Add(dr);

             this .dataGridView2.DataSource  =  mydt;

            MessageBox.Show( " create ok " );

            conn.Open();
            OleDbCommand cmd  =   null ;
             string  id  =   null ;
             string  name  =   null ;
             string  pwd  =   null ;
             string  strSql  =   null ;
             for  ( int  i  =   0 ; i  <=  mydt.Rows.Count  -   1 ; i ++ )
             {
                id = mydt.Rows[i][0].ToString();
                name = mydt.Rows[i][1].ToString();
                pwd = mydt.Rows[i][2].ToString();

                //删除重复记录
                strSql = "delete from MyTable2 where id='" + id + "' and name = '" + name + "' and pwd='" + pwd + "'";
                cmd = new OleDbCommand(strSql, conn);
                cmd.ExecuteNonQuery();
                
                //插入记录
                strSql = "insert into MyTable2 (id,name,pwd) values('" + id + "','" + name + "','" + pwd + "')";
                cmd = new OleDbCommand(strSql, conn);
                cmd.ExecuteNonQuery();

            }             
            OleDbDataAdapter da3  =   new  OleDbDataAdapter( " select * from MyTable2 " , conn);
            DataSet ds3  =   new  DataSet();
            da3.Fill(ds3,  " ds3 " );
             this .dataGridView2.DataSource  =  ds3.Tables[ " ds3 " ];
            conn.Close();