LINQ to SQL -- Can't modify return type of stored procedure.

Question

When I drag a particular stored procedure into the VS 2008 dbml designer, it shows up with Return Type set to "none", and it's read only so I can't change it. The designer code shows it as returning an int, and if I change that manually, it just gets undone on the next build.

But with another (nearly identical) stored procedure, I can change the return type just fine (from "Auto Generated Type" to what I want.)

I've run into this problem on two separate machines. Any idea what's going on?

Here's the stored procedure that works:

USE [studio]
GO
/****** Object:  StoredProcedure [dbo].[GetCourseAnnouncements]    Script Date: 05/29/2009 09:44:51 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER OFF
GO
CREATE PROCEDURE [dbo].[GetCourseAnnouncements]
    @course int
AS
SELECT * FROM Announcements WHERE Announcements.course = @course
RETURN

And this one doesn't:

USE [studio]
GO
/****** Object:  StoredProcedure [dbo].[GetCourseAssignments]    Script Date: 05/29/2009 09:45:32 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER OFF
GO
CREATE PROCEDURE [dbo].[GetCourseAssignments]
    @course int
AS
SELECT * FROM Assignments WHERE Assignments.course = @course ORDER BY date_due ASC
RETURN

Answer 1

Okay, I found the problem... kind of. I had changed the name of the table "Assignments" and forgot to update the stored procudure, so the DBML designer was confused. BUT even after I updated the stored procedure, deleted it from the DBML designer and readded it, it wasn't working!

This is nearly the same problem discussed here: http://forums.asp.net/t/1231821.aspx.

It only worked when I deleted the stored procedure from the database and recreated it, and deleted it from the DBML designer, recompiled, restarted Visual Studio, and added it again. This is the second time I've run into "refresh" problems with the Visual Studio DBML designer...

Answer 2

I've also seen this problem several times and while I don't know what causes it, I've come across a pretty easy way to get past it. It involves manually editing the xml within the .dbml file, but it's a pretty simple edit.

Right-click on your Data Context's .dbml file in the Solution Explorer (not the .layout file nor the designer.cs file) and open it with the XML Editor. You should find your stored procedure listed in a <Function> ... </Function> block. You should also find the custom class you would like to set as the Return Type listed in a <Type> ... </Type> block.

Step one is to give your custom class an identifier. You do so by adding an "Id" tag, like this, making sure that it's unique within the dbml file:

<Type Name="MyCustomClass" Id="ID1">

Step two is to tell your function to use the newly ID'd type as the Return Type. You do so by replacing the line in your <Function> block that looks like

<Return Type="System.Int32" />

with

<ElementType IdRef="ID1" />

Save the file, exit, and rebuild. Done. Re-open the .dbml file in design mode to verify: Your procedure will now have the custom class set as the Return Type.

Answer 3

This also happens when using sql user-defined types as parameters in stored procedures

http://alejandrobog.wordpress.com/2009/09/23/linq-to-sql-%e2%80%94-can%e2%80%99t-modify-return-type-of-stored-procedure/

Answer 4

Hi! I had the same problem, but only happens if my sp uses FTS, what i did was "cheat" the dbml designer, I remove the fts language stuff and works perfectly, now i can change the return type. Later i go to the sp and add the fts again and works pefectly!. Hope this help.

Answer 5

I just recreated the same procedure with a new name and it worked.

Answer 6

Better solution found here: http://tonesdotnetblog.wordpress.com/2010/06/02/solution-my-generated-linq-to-sql-stored-procedure-returns-an-int-when-it-should-return-a-table/