In a desktop application, we also need a login form just like in a web application. I have developed a simple login page in the desktop using Windows Forms.
Login Form Sample
Simple Login Form In Desktop Application Using WinForm
Database Table
  1. CREATE TABLE [dbo].[UserLogin](
  2. [UserID] [INT] IDENTITY(1,1) NOT NULL,
  3. [Username] [VARCHAR](50) NOT NULL,
  4. [Password] [NVARCHAR](250) NOT NULL,
  5. [PasswordSalt] [VARCHAR](50) NULL,
  6. [IsActive] [BIT] NOT NULL,
  7. [AddedOn] [DATETIME] NOT NULL,
  8. CONSTRAINT [PK_UserLogin] PRIMARY KEY CLUSTERED
  9. (
  10. [UserID] ASC
  11. )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
  12. ) ON [PRIMARY]
  13. GO
  14. ALTER TABLE [dbo].[UserLogin] ADD CONSTRAINT [DF_UserLogin_IsActive] DEFAULT ((0)) FOR [IsActive]
  15. GO
  17. Stored Procedure:
  18. -- =============================================
  19. -- Author: <Bhuban Rana>
  20. -- Create date: <2018-12-24>
  21. -- Description: <This Sp checks valid user in userlogin table>
  22. -- =============================================
  23. ALTER PROCEDURE [dbo].[usp_CheckValidUser]
  24. @Username varchar(100),
  25. @Password nvarchar(250)
  26. AS
  27. BEGIN
  28. -- SET NOCOUNT ON added to prevent extra result sets from
  29. -- interfering with SELECT statements.
  30. SET NOCOUNT ON;
  31. DECLARE @Message varchar(100),
  32. @Data nvarchar(250),
  33. @Success bit
  34. IF EXISTS(SELECT * FROM UserLogin WHERE Username=@Username AND [Password]=@Password)
  35. BEGIN
  36. SET @Success=1;
  37. SET @Message='Valid User';
  38. END
  39. ELSE
  40. BEGIN
  41. SET @Success=0;
  42. SET @Message='Incorrect Username or Password!';
  43. END
  44. SELECT @Success AS Success,@Message AS [Message]
  45. END
In Service Class,
  1. public ResponseModel Login(LoginModel model) {
  2. ResponseModel response = new ResponseModel();
  3. try {
  4. using(IDbConnection connection = DbConnection.DbConnect()) {
  5. DynamicParameters parameters = new DynamicParameters();
  6. parameters.Add("@Username", model.Username);
  7. parameters.Add("@Password", model.Password);
  8. response = SqlMapper.Query < ResponseModel > (connection, "[dbo].[usp_CheckValidUser]", parameters, commandType: CommandType.StoredProcedure).FirstOrDefault();
  9. }
  10. } catch (Exception ex) {
  11. response.Success = false;
  12. response.Message = ex.Message.ToString();
  13. }
  14. return response;
  15. }
In Controller,
  1. public class LoginController {
  2. private LoginService _loginService;
  3. public LoginController() {
  4. _loginService = new LoginService();
  5. }
  6. }
Events
  1. private void btnLogin_Click(object sender, EventArgs e) {
  2. progressBar.Minimum = 0;
  3. progressBar.Maximum = 100;
  4. progressBar.Value = 10;
  5. progressBar.Step = 10;
  6. lblRequiredUname.Visible = false;
  7. lblRequiredPwd.Visible = false;
  8. if (string.IsNullOrEmpty(txtUsername.Text) && string.IsNullOrEmpty(txtPassword.Text)) {
  9. lblRequiredUname.Visible = true;
  10. lblRequiredPwd.Visible = true;
  11. } else if (string.IsNullOrEmpty(txtUsername.Text.Trim())) {
  12. lblRequiredUname.Visible = true;
  13. } else if (string.IsNullOrEmpty(txtPassword.Text.Trim())) {
  14. lblRequiredPwd.Visible = true;
  15. } else {
  16. progressBar.Visible = true;
  17. if (!bgWorker.IsBusy) {
  18. btnLogin.Enabled = false;
  19. progressBar.Style = ProgressBarStyle.Marquee;
  20. bgWorker.RunWorkerAsync();
  21. }
  22. }
  23. }
  24. private void bgWorker_DoWork(object sender, DoWorkEventArgs e) {
  25. ResponseModel response = new ResponseModel();
  26. LoginModel model = new LoginModel();
  27. model.Username = txtUsername.Text.Trim();
  28. // model.Password = txtPassword.Text.Trim();
  29. string passwordSalt = string.Empty;
  30. RegistrationModel registrationModel = loginController.GetUserDetailsByUsername(model.Username);
  31. if (registrationModel != null) {
  32. passwordSalt = registrationModel.PasswordSalt;
  33. model.Password = StaticMethods.EncryptString(passwordSalt, txtPassword.Text.Trim());
  34. response = loginController.Login(model);
  35. if (response.Success) {
  36. this.Invoke(new MethodInvoker(delegate() {
  37. this.Hide();
  38. using(Dashboard dashboard = new Dashboard()) {
  39. dashboard.ShowDialog();
  40. }
  41. }));
  42. } else {
  43. this.Invoke(new MethodInvoker(delegate() {
  44. txtUsername.ReadOnly = false;
  45. txtPassword.ReadOnly = false;
  46. }));
  47. btnLogin.Enabled = false;
  48. MessageBox.Show(response.Message, "Fail!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
  49. }
  50. } else {
  51. MessageBox.Show("Please enter valid username..", "Invalid Username!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
  52. }
  53. }
  54. private void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) {
  55. progressBar.Style = ProgressBarStyle.Blocks;
  56. btnLogin.Enabled = true;
  57. }
Conclusion
After login, if the login process is successful, then it redirects to the homepage. Else, it shows an "Invalid Login" error message.