问如何在EF 4.0的SP中使用OutPut参数

EN

CREATE PROCEDURE [dbo].[User_UpdateMessage]
(
@UserId int = 0, 
@UserId2 int = 0,
@Success bit = 0 OUTPUT
)
AS
BEGIN
SET NOCOUNT ON;

IF NOT EXISTS ( SELECT [UserIdFrom] FROM  [dbo].[MessageUpdate] WHERE [UserIdFrom] = @UserId AND [UserIdTo] = @UserId2 )
BEGIN
    INSERT INTO [dbo].[MessageUpdate] ([UserIdFrom], [UserIdTo])
    VALUES (@UserId, @UserId2)
    SELECT @Success = 1;
END
ELSE
    SELECT @Success = 0;
END

// Output Parameter
System.Data.Objects.ObjectParameter paramSuccess1 = 
new System.Data.Objects.ObjectParameter("Success", typeof(byte));
_Entity.User_UpdateMessage(id, userId, paramSuccess1);