How to create winform login dialog and keep looping

Question

Creating a login form that will then proceed to the main form if the credentials are correct. Here is the basic pseudocode:

ShowLoginForm()

if (DialogResul         


        

Answer 1

why not create main form and then show login modal dialog. Then you could check what to do.

Answer 2

How about setting the DialogResult to None in the SubmitButton event handler? Something like:

private void loginButton_Click(object sender, EventArgs e)
{
    if (isValidCredentials())
      DialogResult = DialogResult.OK;
    else
    {
      MessageBox.Show("Failed to login or some other error");
      DialogResult = DialogResult.None;
    }
}

Answer 3

Try this

LoginForm loginForm = new LoginForm();     
do {
   if (loginForm.ShowDialog() == DialogResult.Cancel) {
       return; // Ends application
   }
} while (CheckCredentials() != VALID)
Application.Run(new AutoSignerForm());

Answer 4

I would do the following:

• in Program.cs show the loginForm as a dialog

  LoginForm login_form = new LoginForm();
  if(login_form.ShowDialog() == DialogResult.OK) {
      Application.Run(new MainForm());
  }
  

• in LoginDialog, handle the click event on "Login" button (or whatever is named)

  // replace with the actual login
  if(textBoxUsername.Text == "my user" && textBoxPassword.Text == "my pass") {
     // save the user has logged in somewhere
     // set the dialog result to ok
     this.DialogResult = DialogResult.OK;
     // close the dialog
     this.Close();
  } else {
     // login failed
     MessageBox.show("Login failed");
     // do not close the window
  }
  

Now, you will keep the LoginDialog shown until the user enters valid credentials or he gives up trying and the application closes. This way you will have only one instance of the LoginForm and it will be a nice user experience. Also, you can be sure that the MainForm is not initialized and shown without the user logging in successfully.