I am having a problem returning an output parameter from a Sql Server stored procedure into a C# variable. I have read the other posts concerning this, not only here but on other sites, and I cannot get it to work. Here is what I currently have. Currently I am just trying to print the value that comes back. The following code returns a null value. What I an trying to return is the primary key. I have tried using @@IDENTITY
and SCOPE_INDENTITY()
(i.e. SET @NewId = SCOPE_IDENTITY()
).
Stored Procedure:
CREATE PROCEDURE usp_InsertContract
@ContractNumber varchar(7),
@NewId int OUTPUT
AS
BEGIN
INSERT into [dbo].[Contracts] (ContractNumber)
VALUES (@ContractNumber)
Select @NewId = Id From [dbo].[Contracts] where ContractNumber = @ContractNumber
END
Opening the database:
pvConnectionString = "Server = Desktop-PC\\SQLEXPRESS; Database = PVDatabase; User ID = sa;
PASSWORD = *******; Trusted_Connection = True;";
try
{
pvConnection = new SqlConnection(pvConnectionString);
pvConnection.Open();
}
catch (Exception e)
{
databaseError = true;
}
Executing the command:
pvCommand = new SqlCommand("usp_InsertContract", pvConnection);
pvCommand.Transaction = pvTransaction;
pvCommand.CommandType = CommandType.StoredProcedure;
pvCommand.Parameters.Clear();
pvCommand.Parameters.Add(new SqlParameter("@ContractNumber", contractNumber));
SqlParameter pvNewId = new SqlParameter();
pvNewId.ParameterName = "@NewId";
pvNewId.DbType = DbType.Int32;
pvNewId.Direction = ParameterDirection.Output;
pvCommand.Parameters.Add(pvNewId);
try
{
sqlRows = pvCommand.ExecuteNonQuery();
if (sqlRows > 0)
Debug.Print("New Id Inserted = ",
pvCommand.Parameters["@NewId"].Value.ToString());
}
catch (Exception e)
{
Debug.Print("Insert Exception Type: {0}", e.GetType());
Debug.Print(" Message: {0}", e.Message);
}
}
I slightly modified your stored procedure (to use SCOPE_IDENTITY
) and it looks like this:
CREATE PROCEDURE usp_InsertContract
@ContractNumber varchar(7),
@NewId int OUTPUT
AS
BEGIN
INSERT INTO [dbo].[Contracts] (ContractNumber)
VALUES (@ContractNumber)
SELECT @NewId = SCOPE_IDENTITY()
END
I tried this and it works just fine (with that modified stored procedure):
// define connection and command, in using blocks to ensure disposal
using(SqlConnection conn = new SqlConnection(pvConnectionString ))
using(SqlCommand cmd = new SqlCommand("dbo.usp_InsertContract", conn))
{
cmd.CommandType = CommandType.StoredProcedure;
// set up the parameters
cmd.Parameters.Add("@ContractNumber", SqlDbType.VarChar, 7);
cmd.Parameters.Add("@NewId", SqlDbType.Int).Direction = ParameterDirection.Output;
// set parameter values
cmd.Parameters["@ContractNumber"].Value = contractNumber;
// open connection and execute stored procedure
conn.Open();
cmd.ExecuteNonQuery();
// read output value from @NewId
int contractID = Convert.ToInt32(cmd.Parameters["@NewId"].Value);
conn.Close();
}
Does this work in your environment, too? I can't say why your original code won't work - but when I do this here, VS2010 and SQL Server 2008 R2, it just works flawlessly....
If you don't get back a value - then I suspect your table Contracts
might not really have a column with the IDENTITY
property on it.