In C# how to get return value from stored procedure using ExecuteNonQuery

Question

I have the following query:

create proc [dbo].[DeleteParts] 
    @TransNo nvarchar (6), @fpart nvarchar(25) 
AS 
    DECLARE @Returns BIT 
    SET @Returns =         


        

Answer 1

IF EXISTS(SELECT TransNo FROM [PARTABLE] WHERE TransNo = @TransNo and fpart = @fpart
        BEGIN                       
            DELETE FROM PARTABLE 
                        WHERE TransNo = @TransNo and fpart = @fpart

            SELECT @TransNo AS RETURNVAL
        END
        ELSE
        BEGIN
             SELECT 0 AS RETURNVAL
        END

Answer 2

Naming a variable "@Returns" doesn't magically return it's value, you have to actually return the value.

You can't return a bit value, the return value is always an integer. If you want to sent a bit value back, you would have to use an output parameter instead.

Add a return statement to the procedure:

create proc [dbo].[DeleteParts] 
  @TransNo nvarchar (6), @fpart nvarchar(25) 
AS 
  DECLARE @Returns INT
  SET @Returns = 1 

  BEGIN 
    TRY  
      BEGIN TRANSACTION 

      DELETE FROM PARTABLE 
      WHERE TransNo = @TransNo and fpart = @fpart

      COMMIT 
    END TRY 
    BEGIN CATCH   
       Print 'Delete failed'    
       SET @Returns = 0      
       -- Any Error Occurred during Transaction. Rollback     
       IF @@TRANCOUNT > 0       
           ROLLBACK
    END CATCH

RETURN @Returns

Add a parameter with the direction ReturnValue to receive the return value:

int returnValue;
using(System.Data.SqlClient.SqlCommand deletecommand = this._connection.CreateCommand())
{
   deletecommand.CommandText = "DeleteParts";
   deletecommand.CommandType = System.Data.CommandType.StoredProcedure;
   deletecommand.Parameters.AddWithValue("@TransNo", ItemSODBOM.SONO);
   deletecommand.Parameters.AddWithValue("@fpart", ItemSODBOM.fbompart);
   var returnParameter = deletecommand.Parameters.Add("@ret", SqlDbType.Int);
   returnParameter.Direction = ParameterDirection.ReturnValue;

   deletecommand.ExecuteNonQuery();
   returnValue = (int)returnParameter.Value;
}

Answer 3

Usually the result is returned as a row, like a normal select query would be. You can get at it using a reader or adaptor.

Answer 4

ExecuteNonQuery will return the number of rows affected but NOT data (that's why its a non-query). So it won't bring anything back.

This might be useful to read:

http://www.dreamincode.net/forums/topic/76434-executenonquery-with-output-parameters/

You'll need to use a different mechanism to get your data out - how about ExecuteReader with an output parameter?

Answer 5

ExecuteNonQuery() returns the @@ROWCOUNT which you cannot set. So really you cannot use it to return values.

Answer 6

You need a parameter with Direction set to ParameterDirection.ReturnValue

Something like:

SqlParameter returnParameter = deleteCommand.Parameters.Add("RetVal", SqlDbType.Int);
returnParameter.Direction = ParameterDirection.ReturnValue;
...
deleteCommand.ExecuteNonQuery();
...
int returnValue = (int) returnParameter.Value;

You Stored Procedure needs to return this return value of course:

create proc [dbo].[DeleteParts]      
    @TransNo nvarchar (6),   
    @fpart nvarchar(25)  
AS      
DECLARE @Returns BIT      
SET @Returns = 1     
...
RETURN @Returns