windform 如何创建父子表 在datagrid 中显示

Question

System.Data.DataTable dstab=new System.Data.DataTable();
System.Data.DataTable dstabdet=new System.Data.DataTable();
            System.Data.SqlClient.SqlConnection sqlconn = new System.Data.SqlClient.SqlConnection(sqlconnstr);
            System.Data.SqlClient.SqlCommand sqlcmd = new System.Data.SqlClient.SqlCommand(sql_master, sqlconn);
            System.Data.SqlClient.SqlDataAdapter sqlad = new System.Data.SqlClient.SqlDataAdapter();
            System.Data.SqlClient.SqlCommand sqlcmd_detail = new System.Data.SqlClient.SqlCommand(sql_detail, sqlconn);
            System.Data.SqlClient.SqlDataAdapter sqlad_detail = new System.Data.SqlClient.SqlDataAdapter();
            sqlcmd.CommandText = sqlstr;
            sqlcmd.Connection = sqlconn;
            sqlad.SelectCommand = sqlcmd;
            sqlad.Fill(dstab);            sqlcmd_detail.CommandText = sqlstr_detail;
            sqlcmd_detail.Connection = sqlconn;
            sqlad_detail.SelectCommand = sqlcmd_detail;
            sqlad_detail.Fill(dstabdet);            ds.Tables.Add(dstab);
            ds.Tables.Add(dstabdet);           ds.Relations.Add("masterdetail", ds.Tables[0].Columns[keyword], ds.Tables[1].Columns[keyword]);
           dataGrid1.DataSource = ds.Tables[0].DefaultView;