Question

I have 2 datatables.

One is the master the other is the detail

When someone goes to delete a master record how can I check that there are no rows in my detail datatable that relate to the master table’s ID.

UPDATE: The user has the ability to select more than one master record at a time

I want to use LINQ if possible.

I started looking at DataTable.Rows.Cast()……

Answer 1

You don’t need LINQ for this.

Instead, you can check masterRow.GetChildRows("RelationName").Length.

EDIT: You should use a DataRelation.

If you really don’t want to, you can check

childTable.AsEnumerable().Any(dr => dr["ParentIdColumn"] == someValue)

EDIT: To check for multiple parents:

var parentKeys = parentRows.Select(dr => dr["id"]).ToList();

if (childTable.AsEnumerable().Any(dr => parentKeys.Contains(["ParentIdColumn"])))