how can sqldataobject error be traped

My database has two tables that are joined by a relation (Item category and the item). My relation will not permit the deletion of item categories if there are item referencing it.

How can that error be trapped to then show a message such as. Cannot delete item category that has item associated with it?

This is a asp.net web form with VB

this is the error I get

Server Error in '/TWGSalesInfo' Application.

---

The DELETE statement conflicted with the REFERENCE constraint "FK_PurchaseVendors_PurchaseItems". The conflict occurred in database "CustSegmentation", table "dbo.PurchaseVendors", column 'VendorPurchaseItemID'.
The statement has been terminated.

Description:An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details:System.Data.SqlClient.SqlException: The DELETE statement conflicted with the REFERENCE constraint "FK_PurchaseVendors_PurchaseItems". The conflict occurred in database "CustSegmentation", table "dbo.PurchaseVendors", column 'VendorPurchaseItemID'.
The statement has been terminated.

Source Error:

Line 1904: }Line 1905: try {Line 1906: int returnValue = this.Adapter.DeleteCommand.ExecuteNonQuery();Line 1907: return returnValue;Line 1908: }

Thanks

Dj

Simply add a try/catch block

try

{

int returnValue = this.Adapter.DeleteCommand.ExecuteNonQuery();

return returnValue

}

catch(SqlException)

{

/// throw your custom exception here

throw new MyCustomDeleteException("Unable to delete record...");

}

and in the upper level catch only exceptions of your custom type