Saturday, October 27, 2012

C# Database Tutorials In Urdu (Code) - How to create Login Screen


The code is shown below.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace DatabaseDemo2
{
    public partial class LoginForm : Form
    {
        public LoginForm()
        {
            InitializeComponent();
        }

        private void ExitApplicationButton_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void LoginButton_Click(object sender, EventArgs e)
        {
            if (IsValidated())
            {
                try
                {
                    bool isUserNameCorrect, isPasswordCorrect, isActive;

                    GetIsUserLoginCorrect(out isUserNameCorrect, out isPasswordCorrect, out isActive);

                    if (isUserNameCorrect && isPasswordCorrect)
                    {
                        if (isActive)
                        {
                            this.Hide();

                            if (RememberMeCheckBox.Checked)
                            {
                                Properties.Settings.Default.UserName = UserNameTextBox.Text;
                                Properties.Settings.Default.Save();
                            }

                            ManageStudentsForm msf = new ManageStudentsForm();
                            msf.ShowDialog();
                        }
                        else
                        {
                            MessageBox.Show("Your account is not active. Please consult adminstrator for further info.",
                                            "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);

                            UserNameTextBox.Clear();
                            PasswordTextBox.Clear();
                            UserNameTextBox.Focus();
                        }
                    }
                    else
                    {
                        if(!isUserNameCorrect)
                        {
                            MessageBox.Show("User name is not correct.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                            UserNameTextBox.Clear();
                            PasswordTextBox.Clear();
                            UserNameTextBox.Focus();
                        }
                        else
                        {
                            MessageBox.Show("Password is not correct.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                            PasswordTextBox.Clear();
                            PasswordTextBox.Focus();
                        }
                    }
                }
                catch(ApplicationException ex)
                {
                    MessageBox.Show("Error: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
        }

        private void GetIsUserLoginCorrect(out bool isUserNameCorrect, out bool isPasswordCorrect, out bool isActive)
        {
            string connString = ConfigurationManager.ConnectionStrings["dbx"].ConnectionString;

            using (SqlConnection conn = new SqlConnection(connString))
            {
                using (SqlCommand cmd = new SqlCommand("usp_UserCheckLoginDetails", conn))
                {
                    cmd.CommandType = CommandType.StoredProcedure;

                    conn.Open();

                    // Output Parameter
                    cmd.Parameters.Add("@IsUserNameCorrect", SqlDbType.Bit).Direction = ParameterDirection.Output;
                    cmd.Parameters.Add("@IsPasswordCorrect", SqlDbType.Bit).Direction = ParameterDirection.Output;
                    cmd.Parameters.Add("@IsActive", SqlDbType.Bit).Direction = ParameterDirection.Output;

                    // Parameter
                    cmd.Parameters.AddWithValue("@UserName", UserNameTextBox.Text);
                    cmd.Parameters.AddWithValue("@Password", PasswordTextBox.Text);

                    cmd.ExecuteNonQuery();

                    isUserNameCorrect = (bool)cmd.Parameters["@IsUserNameCorrect"].Value;
                    isPasswordCorrect = (bool)cmd.Parameters["@IsPasswordCorrect"].Value;
                    isActive = (bool)cmd.Parameters["@IsActive"].Value;
                }
            }
        }

        private bool IsValidated()
        {
            if (UserNameTextBox.Text.Trim() == string.Empty)
            {
                MessageBox.Show("UserName is required.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                UserNameTextBox.Clear();
                PasswordTextBox.Clear();
                UserNameTextBox.Focus();
                return false;
            }

            if (PasswordTextBox.Text.Trim() == string.Empty)
            {
                MessageBox.Show("Password is required.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                PasswordTextBox.Clear();
                PasswordTextBox.Focus();
                return false;
            }

            return true;
        }

        private void LoginForm_Load(object sender, EventArgs e)
        {
            UserNameTextBox.Text = Properties.Settings.Default.UserName;
        }
    }
}

Stored Procedure: usp_UserCheckLoginDetails

CREATE PROCEDURE [dbo].[usp_UserCheckLoginDetails]
(
 @IsUserNameCorrect BIT OUTPUT,
 @IsPasswordCorrect BIT OUTPUT,
 @IsActive     BIT OUTPUT,
 @UserName NVARCHAR(50),
 @Password NVARCHAR(50)
)
AS

 BEGIN
  
  SET @IsUserNameCorrect = 0
  SET @IsPasswordCorrect = 0
  SET @IsActive = 0

  IF EXISTS(SELECT * FROM [dbo].[Users] WHERE [UserName] = @UserName 
            AND [Password] = @Password
            AND [IsActive] = 1)
   BEGIN
    SET @IsUserNameCorrect = 1
    SET @IsPasswordCorrect = 1
    SET @IsActive = 1
   END
  ELSE
   BEGIN
    IF EXISTS(SELECT * FROM [dbo].[Users] WHERE [UserName] = @UserName AND [Password] = @Password)
     BEGIN
      SET @IsUserNameCorrect = 1
      SET @IsPasswordCorrect = 1
     END
    ELSE
     BEGIN
      IF EXISTS(SELECT * FROM [dbo].[Users] WHERE [UserName] = @UserName) 
      BEGIN
       SET @IsUserNameCorrect = 1
      END
    
     END
   END
  

 END

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