using a stored procedure for login in c#

If I run a store procedure with two parameter values (admin, admin) (parameters : admin, admin) I get the following message :

Session_UID   User_Group_Name      Sys_User_Name    
------------------------------------ -------------------------------------------------- -
NULLAdministratorsNTMSAdmin
No rows affected.
(1 row(s) returned)
@RETURN_VALUE = 0
Finished running [dbo].[p_SYS_Login].

To get the same message in c# I used the code following :

string strConnection = Settings.Default.ConnectionString;           
using (SqlConnection conn = new SqlConnection(strConnection))
{
    using (SqlCommand cmd = new SqlCommand())
    {
        SqlDataReader rdr = null;
        cmd.Connection = conn;
        cmd.CommandText = "p_SYS_Login";
        cmd.CommandType = CommandType.StoredProcedure;
        SqlParameter paramReturnValue = new SqlParameter();
        paramReturnValue.ParameterName = "@RETURN_VALUE";
        paramReturnValue.SqlDbType = SqlDbType.Int;
        paramReturnValue.SourceColumn = null;
        paramReturnValue.Direction = ParameterDirection.ReturnValue;

        cmd.Parameters.Add(paramReturnValue开发者_开发技巧);

        cmd.Parameters.Add(paramGroupName);
        cmd.Parameters.Add(paramUserName);
        cmd.Parameters.AddWithValue("@Sys_Login", "admin");
        cmd.Parameters.AddWithValue("@Sys_Password", "admin");

        try
        {
            conn.Open();
            rdr = cmd.ExecuteReader();
            string test = (string)cmd.Parameters["@RETURN_VALUE"].Value;
            while (rdr.Read())
            {
               Console.WriteLine("test : " + rdr[0]);
            }
        }
        catch (Exception ex)
        {
            string message = ex.Message;
            string caption = "MAVIS Exception";
            MessageBoxButtons buttons = MessageBoxButtons.OK;

            MessageBox.Show(
            message,
            caption,
            buttons,
            MessageBoxIcon.Warning,
            MessageBoxDefaultButton.Button1);
        }
        finally
        {
            cmd.Dispose();
            conn.Close();
        }
    }
}

but I get nothing in SqlDataReader rdr ; is there something I am missing ?

---

The value at column 0 Session_UID is null as you have shown so I think this may be the reason you are not getting anything here:

Console.WriteLine("test : " + rdr[0]);

but then as an aside you might get Null reference exception.

Still why don't you try this:

Console.WriteLine("Return Value: " + test);

while(rdr.Read()){
    Console.WriteLine("test: " + rdr[0]+"  " + rdr[1]+ "   " + rdr[1]);
}

---

If you want to get back a return value, but no result rows, you shouldn't be using the .ExecuteReader() but rather the .ExecuteNonQuery() call:

try
{
    conn.Open();
    object result = cmd.ExecuteNonQuery();

    string test = (string)cmd.Parameters["@RETURN_VALUE"].Value;
    conn.Close();
}
catch (Exception ex)
{
   ....
}

Also, since you have your SqlCommand in a using.... block, there's really no point in the finally block of your try - the using statement will take care of that already.