从存储过程返回值

Question

I am trying to get data returned from my stored procedure. This is what I have tried and absolutely nothing is coming back.

Stored Proc:

Declare @Submit_ID as int
Set @Submit_ID = (Select (Max(Sub_ID) + 1) from Sub_Details);
INSERT INTO.....
Return @Submit_ID

C# (2.0)

SqlConnection conn = null;
int subid;
try
{
    conn = new SqlConnection(conn_string);
    SqlCommand cmd = new SqlCommand("INSERT_INTO_MYDB", conn);
    cmd.CommandType = CommandType.StoredProcedure;

    SqlParameter p1 = new SqlParameter("@FirstName", SqlDbType.NVarChar, 255);
    p1.Direction = ParameterDirection.Input;
    p1.Value = txtFirstName.Text;
    cmd.Parameters.Add(p1);

    SqlParameter p2 = new SqlParameter("@LastName", SqlDbType.NVarChar, 255);
    p2.Direction = ParameterDirection.Input;
    p2.Value = txtLastName.Text;
    cmd.Parameters.Add(p2);

    SqlParameter pSub = new SqlParameter("@Sub_ID", SqlDbType.Int);
    pSub.Direction = ParameterDirection.ReturnValue;

    conn.Open();
    cmd.ExecuteNonQuery();

    subid = Convert.ToInt32(pSub);
}

Answer 1

You're not adding the return parameter to the command:

SqlParameter pSub = new SqlParameter("@Sub_ID", SqlDbType.Int);
pSub.Direction = ParameterDirection.ReturnValue;

cmd.Parameters.Add(pSub);    // <-------------  add to command

conn.Open();
cmd.ExecuteNonQuery();

subid = Convert.ToInt32(cmd.Parameters["pSub"].Value);

Answer 2

First add parameter to cmd and use .Value to its value

 cmd.Parameters.Add(pSub);    // add parameters to command
 cmd.ExecuteNonQuery();
 subid = Convert.ToInt32(pSub.Value); // Use .Value