Hello @ravi kumar

I have a robust code sample but being robust means it's not a simple copy and paste solution. If you want a simple solution stop here but if you want to do it right continue.

All is explained in the following Microsoft TechNet article.

Details

• There is a table for users and roles which when used in the application provides fine control over a login and checking roles e.g. user or admin.
• Each user is created in the database with permissions set.
• When validating a login user name and password work againsts the last bullet.
• When doing the login user name and password are encrypted then decrypted when there is a need to use them against the database.
• The following script creates the database, users and permissions to the database.
• Frontend project
• Class project for data operations and login validation
• Support class project

  Login form

  using System;
  using System.Windows.Forms;
  using LoginLibrary.DataClasses.DataClasses;
  using LoginLibrary.SecurityClasses.SecurityClasses; namespace SqlCredentialLoginInterface
  {
  public partial class LoginForm
  {
  public LoginForm()
  {
  InitializeComponent();
  }
  private void ShowHidePasswordCheckBox_CheckedChanged(object sender, EventArgs e)
  {
  PasswordTextBox.PasswordChar = ShowHidePasswordCheckBox.Checked ? '*' : '\0';
  }
  /// <summary>
  /// Perform login
  /// </summary>
  /// <param name="sender"></param>
  /// <param name="e"></param>
  private void LoginButton_Click(object sender, EventArgs e)
  {

          if (!string.IsNullOrWhiteSpace(UserNameTextBox.Text) && !string.IsNullOrWhiteSpace(PasswordTextBox.Text))  
          {  
  
              /*  
               * Change server if not using SQLEXPRESS  
               */  
              var ops = new DatabaseUser(".\\SQLEXPRESS", "UserLoginExample");   
  
              var encryption = new Encryption();  
              // encrypt user name and password  
              var userNameBytes = encryption.Encrypt(UserNameTextBox.Text, "111");  
              var passwordBytes = encryption.Encrypt(PasswordTextBox.Text, "111");  
  
              var results = ops.SqlCredentialLogin(userNameBytes, passwordBytes);  
  
              //  
              // Login recognized (does not know if the user has proper permissions to the tables at this point)  
              //  
              if (results.Success)  
              {  
                  Hide();  
                  var mainForm = new MainForm(userNameBytes, passwordBytes);  
                  mainForm.ShowDialog();  
              }  
              else  
              {  
                  MessageBox.Show(results.Message);  
              }  
          }  
          else  
          {  
              MessageBox.Show("Incomplete information to continue.");  
          }  
      }  
      private void CancelButton_Click(object sender, EventArgs e)  
      {  
          Close();  
      }  
  }  
  

  }

  Main form

  using System;
  using System.Linq;
  using System.Windows.Forms;
  using LoginLibrary.DataClasses.DataClasses;
  using LoginLibrary.SupportClasses;
  using SupportLibrary;
  using static SupportLibrary.EnumExtensions; namespace SqlCredentialLoginInterface
  {
  public partial class MainForm
  {

      private readonly byte[] _userNameBytes;  
      private readonly byte[] _userPasswordBytes;  
  
      private readonly BindingSource _productBindingSource = new BindingSource();  
  
      public MainForm(byte[] pNameBytes, byte[] pPasswordBytes)  
      {  
  
          InitializeComponent();  
  
          _userNameBytes = pNameBytes;  
          _userPasswordBytes = pPasswordBytes;  
  
      }  
      private void MainForm_Load(object sender, EventArgs e)  
      {  
  
          var ops = new DataOperations(  
              _userNameBytes,  
              _userPasswordBytes,  
              ".\\SQLEXPRESS",  
              "UserLoginExample", true);  
  
  
  
          var productTable = ops.ReadProductsByCategory(1);  
          if (ops.IsSuccessFul)  
          {  
  
              _productBindingSource.DataSource = productTable;  
              ProductsDataGridView.DataSource = _productBindingSource;  
  
              var controls = this.ButtonList();  
  
              Text = ops.User.Name;  
              if (ops.User.RoleType == RoleTypes.Admin)  
              {  
                  controls.ForEach(b => b.Enabled = true);  
              }  
              else  
              {  
                  controls.Where(b => EnumParser<RoleTypes>(b.Tag.ToString()) == RoleTypes.User)  
                      .ToList().ForEach(b => b.Enabled = true);  
              }  
          }  
          else  
          {  
              MessageBox.Show($"Encountered issues: {ops.LastExceptionMessage}");  
          }  
  
      }  
      private void MainFormClosed(object sender, FormClosedEventArgs e)  
      {  
          Application.ExitThread();  
      }  
  }  
  

  }

  Login form

Main form

If a user is not an admin all three buttons are enabled while for a user button2 is enable while the other two are disabled otherwise all three are enabled.

User table and role table