Getting a Return Value in C# asp.net from a stored procedure (syntax issue)

Question

I am having issues trying to get the syntax correct for my C# 2008 asp.net code. I need to get a return value (Select @@Identity) from my stored procedure

My C# code

Answer 1

The direction is set on a SqlParameter object, for your example it should be something like:

cmdHeader.Parameters["@Postal_Code"].Direction = ParameterDirection.ReturnValue;

Answer 2

To capture a RETURN VALUE (returned by SQL using the RETURN({number}) syntax) use:

cmdHeader.Parameters.Add("@ReturnValue", SqlDbType.Int, 4).Direction = ParameterDirection.ReturnValue;

Also, you should probably be using SCOPE_IDENTITY() instead of @@IDENTITY

Edit:
So your sproc would do something like:

DECLARE @NewId INTEGER
INSERT SomeTable(FieldA) VALUES ('Something')
SELECT @NewId = SCOPE_IDENTITY()
RETURN (@NewId)

And your C# code to retrieve that value would be:

int newId = cmdHeader.Parameters[@ReturnValue].value;

Edit 2:
Ok, the original question confused the issue as the "return value" is a different thing to what you're actually doing which is returning a single column resultset.

So, instead DON'T add a ReturnValue parameter at all. Just use ExecuteScalar() using your original SqlCommand setup as below:

int newId = Convert.ToInt32(cmdHeader.ExecuteScalar());

Answer 3

SQL Stored Procedure:

Assume procedure returns some id/ identity as shown below

SET @ReturnValue= Scope_identity() return @ReturnValue

in C# we can

SqlParameter[] param = null; param = new SqlParameter[] { new SqlParameter("@idStudent",idStudent), new SqlParameter("","") // some empty parameters for return value }

//here we can update param with return type SqlParameter parOut = new SqlParameter("@ReturnValue", 0); parOut.Direction = ParameterDirection.Output; param[param.Length - 1] = parOut;

DataSet dsResult = con.executeSelectStoredProc("SP_NAME", param);

Answer 4

SqlParameter parameterReturnValue = new SqlParameter("ReturnValue", SqlDbType.Int, 4);
parameterReturnValue.Direction = ParameterDirection.ReturnValue;
cmdHeader.Parameters.Add(parameterReturnValue);

//Execute your command
cmdHeader.ExecuteNonQuery();

//Get the return value
int returnvalue = (int)myCommand.Parameters["ReturnValue"].Value;