Calling stored procedure with return value

Question

I am trying to call a stored procedure from my C# windows application. The stored procedure is running on a local instance of SQL Server 2008. I am able to call the stored procedure but I am not able to retrieve the value back from the stored procedure. This stored procedure is supposed to return the next number in the sequence. I have done research online and all the sites I've seen have pointed to this solution working.

Stored procedure code:

ALTER procedure [dbo].[usp_GetNewSeqVal]
      @SeqName nvarchar(255)
as
begin
      declare @NewSeqVal int
      set NOCOUNT ON
      update AllSequences
      set @NewSeqVal = CurrVal = CurrVal+Incr
      where SeqName = @SeqName

      if @@rowcount = 0 begin
print 'Sequence does not exist'
            return
      end

      return @NewSeqVal
end

Code calling the stored procedure:

SqlConnection conn = new SqlConnection(getConnectionString());
conn.Open();

SqlCommand cmd = new SqlCommand(parameterStatement.getQuery(), conn);
cmd.CommandType = CommandType.StoredProcedure;

SqlParameter param = new SqlParameter();

param = cmd.Parameters.Add("@SeqName", SqlDbType.NVarChar);
param.Direction = ParameterDirection.Input;
param.Value = "SeqName";

SqlDataReader reader = cmd.ExecuteReader();

I have also tried using a DataSet to retrieve the return value with the same result. What am I missing to get the return value from my stored procedure? If more information is needed, please let me know.

Solution 1

You need to add return parameter to the command:

using (SqlConnection conn = new SqlConnection(getConnectionString()))
using (SqlCommand cmd = conn.CreateCommand())
{
    cmd.CommandText = parameterStatement.getQuery();
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.AddWithValue("SeqName", "SeqNameValue");

    var returnParameter = cmd.Parameters.Add("@ReturnVal", SqlDbType.Int);
    returnParameter.Direction = ParameterDirection.ReturnValue;

    conn.Open();
    cmd.ExecuteNonQuery();
    var result = returnParameter.Value;
}

Solution 2

I know this is old, but i stumbled on it with Google.

If you have a return value in your stored procedure say "Return 1" - not using output parameters.

You can do the following - "@RETURN_VALUE" is silently added to every command object. NO NEED TO EXPLICITLY ADD

    cmd.ExecuteNonQuery();
    rtn = (int)cmd.Parameters["@RETURN_VALUE"].Value;

Solution 3

The version of EnterpriseLibrary on my machine had other parameters. This was working:

        SqlParameter retval = new SqlParameter("@ReturnValue", System.Data.SqlDbType.Int);
        retval.Direction = System.Data.ParameterDirection.ReturnValue;
        cmd.Parameters.Add(retval);
        db.ExecuteNonQuery(cmd);
        object o = cmd.Parameters["@ReturnValue"].Value;

Solution 4

This is a very short sample of returning a single value from a procedure:

SQL:

CREATE PROCEDURE [dbo].[MakeDouble] @InpVal int AS BEGIN 
SELECT @InpVal * 2; RETURN 0; 
END

C#-code:

int inpVal = 11;
string retVal = "?";
using (var sqlCon = new SqlConnection(
    "Data Source = . ; Initial Catalog = SampleDb; Integrated Security = True;"))
{
    sqlCon.Open();
    retVal = new SqlCommand("Exec dbo.MakeDouble " + inpVal + ";", 
        sqlCon).ExecuteScalar().ToString();
    sqlCon.Close();
}
Debug.Print(inpVal + " * 2 = " + retVal); 
//> 11 * 2 = 22

Solution 5

I had a similar problem with the SP call returning an error that an expected parameter was not included. My code was as follows.
Stored Procedure:

@Result int OUTPUT

And C#:

            SqlParameter result = cmd.Parameters.Add(new SqlParameter("@Result", DbType.Int32));
            result.Direction = ParameterDirection.ReturnValue;

In troubleshooting, I realized that the stored procedure was ACTUALLY looking for a direction of "InputOutput" so the following change fixed the problem.

            r

Result.Direction = ParameterDirection.InputOutput;

View more solutions

Comments

[muttley91]

Do you have to add @ReturnVal to the Stored Procedure as well?

[Michael]

Hi Gary. Do you happen to have a citation?

[ufosnowcat]

No, you don't have to add to the sp (the return statement triggers filling the parameter marked with ReturnValue)

[Soori]

ExecuteScalar() doesn't work, unless you "select" the return value.

[Clay]

Doesn't matter what you name the return val parameter, btw.

[jb007]

I dont believe that the cmd instance will have a parameter named in RETURN_VALUE in the SqlParameterCollection unless it is added explicitly. Therefore, if you are considering taking the approach above by Gary, then ensure you have added cmd.Parameters.Add(new SqlParameter("@RETURN_VALUE", SqlDbType.Int)); cmd.Parameters["@RETURN_VALUE"].Direction = ParameterDirection.ReturnValue; However, I do believe that you DO NOT have to add the @RETURN_VALUE to the stored procedure definition. Perhaps that is what Gary meant.

[Oswaldo Zapata]

thanks a lot, I was looking for a way to properly get return value, this really worked for me. awesome!

[tony09uk]

Looking through SqlDbType enumeration, all the types are for returning only a single value. How do you define that a table of data is being returned?

[Manuel Hoffmann]

@tony09uk I don't think ReturnValue supports that. But you can simply not use return in your procedure and instead end the procedure with SELECT * FROM tableToReturn. In your programm, use an SqlDataAdapter to get the table from the select statement in your stored procedure just like you would get get the result of a normal SQL statement.

[Dan Guzman]

The stored procedure return value should be used only to indicate success (zero) or failure/warning (non-zero), not return data. Use an OUTPUT parameter or result set for that purpose.

[Dai]

"Output parameters" are not the same thing as Stored Procedure return-values, btw.