DataRelation myDataRelation;
myDataRelation = new DataRelation("CustOrd", ds.Tables["Customers"].Columns["CustomerID"], ds.Tables["Orders"].Columns["CustomerID"]);
// Add the relation to the DataSet.
ds.Relations.Add(myDataRelation);
GridOrders.SetDataBinding(ds,"Customers");
GridDetails.SetDataBinding(ds,"Customers.CustOrd");