Trying to create a master/detail datagrid

[drewmace]

I know this is probably a simple answer but it is escaping me.! I am trying to create a master datagrid that has a detail datagrid nested in it. The relationship is 1..n or possible 1..null. I have incluided a clip of the code below. I am loading the Child Rows to a new dataset and trying to make the datasource of the detail datagrid that dataset...i keep getting the error "Object reference not set to an instance of an object."

TIA
Drew

LicenseDG.DataSource=dv;
LicenseDG.DataBind();

DataRow[] rows = ds.Tables["Agents"].Rows[0].GetChildRows(agentlicense);
DataSet tmpData = new DataSet();
tmpData.Merge(rows);

dg2.DataSource=tmpData.Tables[0].DefaultView;