How can I close a login form and show the main for

Question

I have two forms in my project (Login and Main).

What I'm trying to accoomplish is, if the login is successful, I must show the Main form and close the Login form.

I have this method in Login form that closes the Login form when the login is successful. But the Main form doesn't show.

public void ShowMain()
{
    if(auth()) // a method that returns true when the user exists.
    {             
        var main = new Main();
        main.Show();
        this.Close();
    }
    else
    {
        MessageBox.Show("Invalid login details.");
    }         
}

I tried hiding the Login form if the login process is successful. But it bothers me because I know while my program is running the login form is still there too, it should be closed right?

What should be the right approach for this? Thanks...

Answer 1

It's simple.

Here is the code.

 private void button1_Click(object sender, EventArgs e)
 {  
        //creating instance of main form
        MainForm mainForm = new MainForm();

        // creating event handler to catch the main form closed event
        // this will fire when mainForm closed
        mainForm.FormClosed += new FormClosedEventHandler(mainForm_FormClosed);
        //showing the main form
        mainForm.Show();
        //hiding the current form
        this.Hide();
  }

  // this is the method block executes when main form is closed
  void mainForm_FormClosed(object sender, FormClosedEventArgs e)
  {
       // here you can do anything

       // we will close the application
       Application.Exit();
  }

Answer 2

This is my solution. Create ApplicationContext to set mainform of application and change mainform when you want to open new form and close current form.

Program.cs

static class Program
{
    static ApplicationContext MainContext = new ApplicationContext();

    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);

        MainContext.MainForm = new Authenticate();
        Application.Run(MainContext);
    }

    public static void SetMainForm(Form MainForm)
    {
        MainContext.MainForm = MainForm;
    }

    public static void ShowMainForm()
    {
        MainContext.MainForm.Show();
    }
}

When login process is complete.

private void BtLogin_Click(object sender, EventArgs e)
    {
        //Login Process Here.

        Program.SetMainForm(new Portal());
        Program.ShowMainForm();

        this.Close();
    }

I hope this will help you.

Answer 3

you should do it the other way round:

Load the mainform first and in its onload event show your loginform with showdialog() which will prevent mainform from showing until you have a result from the loginform

EDIT: As this is a login form and if you do not need any variables from your mainform (which is bad design in practice), you should really implement it in your program.cs as Davide and Cody suggested.

Answer 4

best way for show login for and close login form before login successfully put login form in FrmMain after InitializeComponent.

 public FrmMain()
 {
      FrmSplash FrmSplash = new FrmSplash();
      FrmSplash.ShowDialog();

      InitializeComponent();
      //Login Section
 {

Answer 5

This is the most elegant solution.

private void buttonLogin_Click(object sender, EventArgs e)
{
    MainForm mainForm = new MainForm();
    this.Hide();
    mainForm.ShowDialog();
    this.Close();
}

;-)

Answer 6

I would do this the other way round.

In the OnLoad event for your Main form show the Logon form as a dialog. If the dialog result of that is OK then allow Main to continue loading, if the result is authentication failure then abort the load and show the message box.

EDIT Code sample(s)

private void MainForm_Load(object sender, EventArgs e)
{
    this.Hide();

    LogonForm logon = new LogonForm();

    if (logon.ShowDialog() != DialogResult.OK)
    {
        //Handle authentication failures as necessary, for example:
        Application.Exit();
    }
    else
    {
        this.Show();
    }
}

Another solution would be to show the LogonForm from the Main method in program.cs, something like this:

static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);

    LogonForm logon = new LogonForm();

    Application.Run(logon);

    if (logon.LogonSuccessful)
    {
        Application.Run(new MainForm());
    }
}

In this example your LogonForm would have to expose out a LogonSuccessful bool property that is set to true when the user has entered valid credentials