Question

I am changing a console app login over to a web based application and recieve the following error about an Unhandled exception.

In the console app I have the following line of code which resides in the StoredProcDemo class:

 StoredProcDemo spd = new StoredProcDemo();

In the Web Application I have:

Login spd = new Login(); 

I am not sure what to change it over to. Could someone shed some insight thanks and maybe why? Thanks so much.

Here is the full code if needed.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Data.Sql;
using System.Data.SqlTypes;

namespace GUI_Login
{
    public partial class Login : System.Web.UI.Page
    {
            SqlConnection conn = null;
            SqlParameter parmReturnValue;

            Login spd = new Login();

        protected void Page_Load(object sender, EventArgs e)
        {   
        }

        protected void btnLogin_Click(object sender, EventArgs e)
        {
            RunStoredProcParams();
        }

        public void RunStoredProcParams()
        {
            //run simple stored procure
            spd.RunStoredProcParams();

            int Result;
            Result = -1;

            conn = conn = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=c:\\Program Files\\Microsoft SQL Server\\MSSQL10.SQLEXPRESS\\MSSQL\\DATA\\UserDB.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True; Integrated Security=SSPI");
            conn.Open();

            try
            {
                //create and open a connection object
                conn = conn = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=c:\\Program Files\\Microsoft SQL Server\\MSSQL10.SQLEXPRESS\\MSSQL\\DATA\\UserDB.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True; Integrated Security=SSPI");
                conn.Open();

                //Create the command object indentifying the stored procedure
                SqlCommand cmd = new SqlCommand("PassParamUserID", conn);

                //set the command object so it knows to execute a stored procedure
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.Add(new SqlParameter("@FirstName", txtUserName.Text));
                parmReturnValue = cmd.Parameters.AddWithValue("@UserId", SqlDbType.Int);
                parmReturnValue.Direction = ParameterDirection.ReturnValue;

                cmd.ExecuteNonQuery();
                Result = Convert.ToInt32(cmd.Parameters["@UserId"].Value);
                conn.Close();

                // lblResult.Text = Result;
                if (Result > 0)
                {
                    lblResult.Text = ("User does exist in database");
                }
                else if (Result < 0)
                {
                    lblResult.Text = ("Denied, try another user name");
                }
            }
            finally
            {
                if (conn != null)
                {
                    conn.Close();
                }
            }

        }

Answer 1

Even ignoring RunStoredProcParams you’ll get a stack overflow as soon as you try to create a new instance:

public partial class Login : System.Web.UI.Page
{
    // Removed extraneous stuff...
    Login spd = new Login();
}

Why do you want every instance of Login to have a reference to another instance of Login, which it creates immediately?

Basically the constructor is going to be called recursively until it goes bang.

What are you trying to do here, and why? In the console app you may well be creating an instance of StoredProcDemo, but I’m sure it wouldn’t be within StoredProcDemo itself (as an instance variable initializer). Perhaps it’s in Program or something similar? That would make more sense.