Compare sql query result and user input

[BlackNinja]

Hello folks, I'm a little stuck and any help would be appreciated. Basically what I'm trying to do is have the user enter a pin or password, connect to a database and check whether that password is in there, if it is the program will switch to a new form. The problem is i don't know how to compare the query result with what the user has entered into the textbox. Below is my code.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using MySql.Data.MySqlClient;

namespace FullProject
{
    public partial class Form1 : Form
    {
        //Making form 1 static so i can get back to it from form 2 and making pin public so form 2 can use it
        public static Form1 staticf = null;
        public static string ent = null;

        public Form1()
        {
            InitializeComponent();
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            //Only 6 characters can be entered in textbox
            textBox1.MaxLength = 6;
        }

        private void enter_Click(object sender, EventArgs e)
        {
            //ent now equals the textbox
            ent = textBox1.Text;

            //Opening connection to database and execute query
            MySqlConnection condatabase = new MySqlConnection("Data Source=localhost;" + "Persist Security Info=yes;" +
                "UserID = root; PWD= ;");
            MySqlCommand cmddatabase = new MySqlCommand("Use winc; Select pin From info Where pin = [box]" + ent);

            condatabase.Open();

            MySqlDataReader reader = cmddatabase.ExecuteReader();
            string res = cmddatabase.ToString;

            //If pin exists in database execute statement inside the if, ignore if condition as it was being used for testing
            if (textBox1.Text == "1234")
            {
                staticf = this;
                this.Hide();
                textBox1.Text = null;

                Form2 form2 = new Form2();
                form2.Show();
            }

            else
            {
                //Display if pin isnt found in database
                MessageBox.Show("Incorrect pin entered");
            }
        }
    }
}

[rohini deepu]

Hai,

Instead of selecting the password first and then compare,
you can compare the username and password using sql query...

IF EXISTS(SELECT username FROM table1
	  WHERE username=txtUsername.text
          AND password=txtPassword.text
	 )
	 SELECT 1
ELSE
	 SELECT 0

This query returns 1 if such a user exists or 0 if not exists.
Hope this will help you...

[Geekitygeek]

Also, I would recommend checking my tutorial on accessing form controls/members from other forms.
Your 'ent' variable is specific to the current instance of the form, static members should be common across all instances. My tutorial shows how to use a property to access a private member. Properties are a better OO practice as they provide Encapsulation.

Having checked your code, however, i think you can eliminate the need to access the data on Form1 from Form2 by passing the user input to Form2 in its constructor:

public partial class Form2 : Form
{
    private string ent; //move your ent INTO form2
     
    public Form2(string UserEnteredText)    {
        InitializeComponent();
        ent = UserEnteredText;
    }
 }

  //then call it like this:

Form2 frm = new Form2(this.TextBox1.Text);
frm.Show();

EDIT: also, check out my new snippet to show how to show/hide a form when calling a new form

[BlackNinja]

I'm sorry but i just don't understand where that if statement should go rohini.

[Geekitygeek]

As he said, the code given is an alternative SQL query, place it where your current query is.
Did you check any of the snippets i linked you to?