System.InvalidCastException: Unable to cast object of type 'System.Int64' to type 'System.String'.

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i am using linq and asp.net ...the code is below

C#

public static List<category> getPopularCategories() 
{
    clsCityPageDataContext cox = new clsCityPageDataContext();
    var cats = from cat in cox.Categories 
               select cat;
    return cats.ToList<category>().GetRange(0,10);
}

it get result from

SQL

USE [cpDB]
GO

DECLARE	@return_value int

EXEC	@return_value = [dbo].[Directory_GetPopularCategories]

SELECT	'Return Value' = @return_value

GO

........
i am getting
System.InvalidCastException: Unable to cast object of type 'System.Int64' to type 'System.String'.error
can any one help me?

Posted 10-May-11 3:06am

Member 7911856

Updated 10-May-11 3:13am

#realJSOP

v3

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jim lahey · Answer 1 · 2011-05-10T03:11:00

Solution 1

change this:

SQL

DECLARE	@return_value int

to:

SQL

DECLARE	@return_value nvarchar(MAX)

Posted 10-May-11 3:11am

jim lahey

Comments

Member 7911856 10-May-11 9:16am

i am doing this but the sp do not updated succesfully....how can i update my sp?

jim lahey 10-May-11 9:23am

When you edit the SP in SMSS, you'll see it's wrapped in an ALTER statement.. click on the button what says Execute

Member 7911856 10-May-11 9:29am

when i right click on my sp and click modify..i get
ALTER PROCEDURE [dbo].[Directory_GetPopularCategories]

AS
BEGIN

Select Top 5 * from Categories Order by Hits
END
.......when i click execute sp ..i get
USE [cpDB]
GO

DECLARE @return_value int

EXEC @return_value = [dbo].[Directory_GetPopularCategories]

SELECT 'Return Value' = @return_value

GO
here i change ur statment like

DECLARE @return_value nvarchar(MAX)
and execute it,but no result....

keyur satyadev · Answer 2 · 2011-05-10T03:15:00

SQL

check it twice. some where it requires string value and you are passing int value (based on your error description). so it will give you the error.

Hint : error is in below portion of code.
DECLARE @return_value int
EXEC @return_value = [dbo].[Directory_GetPopularCategories]
SELECT 'Return Value' = @return_value

#realJSOP · Answer 3 · 2011-05-10T03:17:00

Solution 3

BTW, why are you using linq to get the list? Why not just do this:

C#

List<category> cats = cox.Categories.GetRange(0, Math.Min(10, cox.Categories));

It will throw an exception if you specify more items than what exists in the list, that's why I used Math.Min.

Posted 10-May-11 3:17am

#realJSOP

Updated 10-May-11 3:18am

v2

Comments

Member 7911856 10-May-11 9:22am

i use this
public static List<category> getPopularCategories() {
clsCityPageDataContext cox = new clsCityPageDataContext();
return List<category> cats = cox.Categories.GetRange(0, Math.Min(10, cox.Categories));
}
this gives me error
CS0305: Using the generic type 'System.Collections.Generic.List<t>' requires '1' type arguments

#realJSOP 10-May-11 11:18am

Are you completely incapable of figuring out what's wrong by using, oh, I don't know... the DEBUGGER!?