how to make successful login close LoginView in WPF MVVM application?

Question

I have a WPF application in MVVM architecture. When the application loads I need to show a 'Login' window where the user inputs username and password.

This is then passed to a ServiceLocator, which creates a client that connects to the WCF service.

Question :

How do I make the 'Login' window close once the client has successfully connected, without using any code-behind in the View's '.cs' file ?

Hide the main window. Show it in case of successful login. Login window should be handled as any other dialog in MVVM. — Den, Jul 12 '12 at 07:58

score 1 · Answer 1 · answered Jul 12 '12 at 08:24

I normally pass the ViewModel a Close Action in the IDialogService implementation.

public void ShowDialog(IDialogViewModel vm)
{
    // create the dialog view
    ...
    vm.CloseAction = () => dialog.Close();
    dialog.DataContext = vm;
    ...
    // show the dialog 
    dialog.ShowDialog();
}

score 0 · Answer 2 · edited May 23 '17 at 12:24

0

I use a dialogservice for my login and expose an event

event EventHandler<RequestCloseEventArgs> RequestCloseDialog;

which closes the dialog when the client succesfully looged in.

edit: Here's an example

In your app.xaml.cs

protected override void OnStartup(StartupEventArgs e)
{
    var result = this._dialogService.Show("Login",this._myloginviewmodel);

    // When use click cancel in the login dialog
    if(!result)
    { 
        // Close app or whatever
    }

    // Access the properties of myloginviewmodel if you want

    // Now the only part of my app where I use view-first instead of viewmodel-first
    this.MainWindow = new MainWindow(_mainwindowviwemodel);
    this.MainWindow.Show();
}

That's all in my OnStartup(), and yes thats the codebehind from my app.xaml, but this is my application root and thats why this is ok for me. I don't have a AppViewModel or something like that because app.xaml will never "shown" to the user.

edited May 23 '17 at 12:24

Community

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answered Jul 12 '12 at 07:17

blindmeis

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how do you use it in the 'OnStartup' ? can you please post a code sample ? – John Miner Jul 12 '12 at 11:57
and like @pchajer said : doesn't this violate the MVVM as the logic are written in code behind which is against the MVVM ? – John Miner Jul 12 '12 at 11:58
no, because i have no viewmodel with a reference to the view. and the app.xaml.cs its not a "view codebehind" for me - its my application root. – blindmeis Jul 13 '12 at 05:54

score 0 · Answer 3 · answered Jul 12 '12 at 07:21

0

You can override OnStartup method of Application class, where you can open the Login screen as a dialog, once user enter valid data you can return boolean value, on closing of login screen, you can do your further logic based on the boolean value.

answered Jul 12 '12 at 07:21

pchajer

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how to make successful login close LoginView in WPF MVVM application?

3 Answers3