Question

I have created a Stored Procedure that generates a GUID and then returns it as a NVARCHAR, however when trying to access it using LINQ to SQL it is not being recognized as an ISingleResult. I have created numerous other procedures that have worked as expected such as:

CREATE PROCEDURE [dbo].[GetContact]
    @ContactID [int]
AS
BEGIN

    SET NOCOUNT ON;

SELECT
    ContactID,
    PrefixTypeID,
    FirstName,
    MiddleName,
    LastName,
    Suffix,
    LanguageTypeID,
    Organization,
    OrganizationLocation,
    OrganizationDepartmentTypeID,
    OrganizationEmployeeID,
    JobTitleID,
    TimeZone,
    AccountID,
    PortalID,
    CorporateAccountID,
    ContactRelationshipTypeID,
    EthnicityID,
    CitizenshipID,
    EducationID,
    ContactSalaryRangeID,
    Age,
    Birthday,
    IsMarried,
    LeadSourceTypeID
FROM Contact
WHERE ContactID = @ContactID 

END

---

using (Data.Contact.ContactDataContext contactDC = new Data.Contact.ContactDataContext())
{
    Data.Contact.GetContactResult contactResult = contactDC.GetContact(this.ID).SingleOrDefault();
}

However when I try to accomplish the same thing using the following Procedure I get the following error Cannot implicitly convert type 'System.Data.Linq.ISingleResult <OTS.Data.Application.GetSessionResult>' to 'OTS.Data.Application.GetSessionResult'. An explicit conversion exists (are you missing a cast?)

CREATE PROCECURE [dbo].[GetSession]

AS

    DECLARE @SessionID [nvarchar](38) = NEWID()

    INSERT INTO SessionTable (SessionID) VALUES (@SessionID)

    SELECT @SessionID As SessionID

When I run this in SSMS it returns the correct data, however in LINQ it does not. The other questions I’ve found similar to this one have either been unanswered or the answer was to not use LINQ. Is there a way to accomplish this using LINQ?

UPDATE

---

The code for GetSession is exactly the same as the GetContact. I have tried casting it but receive the error listed above.

The issue I’m experiencing is similar to this: Question about linq2sql

However we have tried removing and re-creating the dbml with no success…not only that but all new procedures that are created are now producing the same issue.

Using a UDF gives the output I need, however it does not work for my application. In my procedures I am checking for the existence of records before returning the data.

example

CREATE PROCEDURE [dbo].[GetPage]
    @PageName [nvarchar](255),
    @PagePath [nvarchar](255)
AS
BEGIN

    SET NOCOUNTON;

    DECLARE @PageID [int]

    IF NOT EXISTS(SELECT PageID FROM Page WHERE PagePath = @PagePath)
        BEGIN
            INSERT INTO Page(PageName, PagePath)
            VALUES(@PageName, @PagePath)

            SET @PageID = SCOPE_IDENTITY()
        END
    ELSE
        BEGIN
            SELECT @PageID = PageID
            FROM Page
            WHERE PagePath = @PagePath
        END

    --For the return values I have tried both ways below with the same results
    --ReQuery DB for data
    SELECT PageID, PageName, PagePath
    FROM Page
    WHERE PageID = @PageID

    --Query the Variables
    SELECT @PageID AS PageID, @PageName AS PageName, @PagePath AS PagePath

END

With the inability to do an INSERT or an EXEC inside of a UDF I cannot use them and need to use a SP. Any ideas are appreciated.

Answer 1

Oversight

Make sure that you do not forget to include using System.Data.Linq as well as your data context.