Login Window in WPF Prism - wpf

Question

I'm implementing a login window before my shell runs. How will I run the code and say that after authentication in the login window, proceed with the execution of shell application.
Here is my initial code:
LoginViewModel.cs
public event EventHandler LoginCompleted;
private void RaiseLoginCompletedEvent()
{
LoginCompleted?.Invoke(this, EventArgs.Empty);
}
Bootstraper.cs from the Shell
My problem here is that I cannot instantiate my LoginModel since the constructor of my Model has a parameter to use my Services Interface.
Is there any solution for this? Thanks!

Answer 1

New up an instance of a class that implements the ILoginAuth interface yourself:
var loginVM = new LoginViewModel(new LoginAuth());
...or let the container do it for you:
var loginVM = new LoginViewModel(Container.Resolve<ILoginAuth>());
For the latter option to work, you must register your type mappings by overriding the RegisterTypes method:
protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
containerRegistry.Register<ILoginAuth, LoginAuth>();
}

Answer 2

Another method of doing this:
ILoginAuth auth = CommonServiceLocator.ServiceLocator.Current.GetInstance<ILoginAuth>();
This way you don't have to include ILoginAuth in your constructor. Also, you can do this from any where!

Answer 3

<pre>
/*Brian code modified */
public interface ICloseWindow {
Action Close {
get;
set;
}
}
public partial class LoginWindow: Window {
public LoginWindow(ILoginViewModel viewModel) {
InitializeComponent();
DataContext = viewModel;
Loaded += MainWindow_Loaded;
}
private void MainWindow_Loaded(object sender, RoutedEventArgs e) {
if (DataContext is ICloseWindow vm) {
vm.Close += () =>{
DialogResult = true;
};
}
}
private void Close_Window(object sender, RoutedEventArgs e) {
DialogResult = false;
}
}
/*App.xaml.cs*/
protected override void InitializeShell(Window shell) {
Window login = Container.Resolve < LoginWindow > ();
var result = login.ShowDialog();
if (!result.Value) {
Application.Current.Shutdown();
}
else {
base.InitializeShell(shell);
}
}
public class LoginViewModel: BindableBase,
ILoginViewModel,
ICloseWindow {
private string _userName;
private string _password;
private bool _isAuthenticated;
private ICommand _authenticateUserCommand;
private IEventAggregator _eventAggregator;
public Action Close {
get;
set;
}
public ICommand AuthenticateUserCommand {
get =>_authenticateUserCommand;
set =>_authenticateUserCommand = value;
}
public LoginViewModel(IEventAggregator eventAggregator) {
AuthenticateUserCommand = new DelegateCommand < object > (AuthenticateUser);
_eventAggregator = eventAggregator;
}
private void AuthenticateUser(object parameter) {
var passwordBox = parameter as PasswordBox;
var password = passwordBox.Password;
if (password == "password") {
_isAuthenticated = true;
_eventAggregator.GetEvent < MessageSentEvent > ().Publish("Login Data");
}
if (_isAuthenticated) {
Close ? .Invoke();
}
}
public string UserName {
get =>_userName;
set =>_userName = value;
}
public string Password {
get {
return _password;
}
set {
if (_password != value) {
_password = value;
RaisePropertyChanged(nameof(Password));
}
}
}
}
<Window x:Class="YourApplication.Views.LoginWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:YourApplication"
mc:Ignorable="d"
Title="LoginWindow"
Height="450"
Width="800"
WindowStartupLocation="CenterScreen"
WindowStyle="None"
x:Name="WindowBorder"
RenderOptions.BitmapScalingMode="HighQuality">
<Grid SnapsToDevicePixels="True"
UseLayoutRounding="True"
TextOptions.TextFormattingMode="Display"
TextOptions.TextRenderingMode="ClearType">
<DockPanel>
<DockPanel DockPanel.Dock="Left"
Width="400"
LastChildFill="True">
<Canvas>
<Canvas.Background>
<ImageBrush ImageSource="pack://application:,,,/YourApplication;component/Images/Splash.png" />
</Canvas.Background>
<TextBlock Margin="4,0,0,4"
VerticalAlignment="Center"
Foreground="#FFAAAAAA"
TextWrapping="NoWrap"
Text="Library Management System"
FontSize="16"
Background="Transparent"
DockPanel.Dock="Top" />
</Canvas>
</DockPanel>
<DockPanel LastChildFill="True">
<Button x:Name="PART_CLOSE"
DockPanel.Dock="Top"
HorizontalAlignment="Right"
VerticalAlignment="Center"
Margin="5"
Height="20"
Width="20"
Style="{DynamicResource MetroWindowButtonStyle}"
Click="Close_Window">
<Path Data="F1M54.0573,47.8776L38.1771,31.9974 54.0547,16.1198C55.7604,14.4141 55.7604,11.6511 54.0573,9.94531 52.3516,8.23962 49.5859,8.23962 47.8802,9.94531L32.0026,25.8229 16.1224,9.94531C14.4167,8.23962 11.6511,8.23962 9.94794,9.94531 8.24219,11.6511 8.24219,14.4141 9.94794,16.1198L25.8255,32 9.94794,47.8776C8.24219,49.5834 8.24219,52.3477 9.94794,54.0534 11.6511,55.7572 14.4167,55.7585 16.1224,54.0534L32.0026,38.1745 47.8802,54.0534C49.5859,55.7585 52.3516,55.7572 54.0573,54.0534 55.7604,52.3477 55.763,49.5834 54.0573,47.8776z"
Stretch="Uniform"
Fill="#FFAAAAAA"
Width="10"
Margin="0,0,0,0"></Path>
</Button>
<StackPanel>
<PasswordBox x:Name="txtPassword"
Margin="2,20,10,10"
Height="22"
Width="100" />
<Button Width="100"
Height="22"
Margin="10,150,10,10"
Content="Login"
Command="{Binding AuthenticateUserCommand}"
CommandParameter="{Binding ElementName=txtPassword}" />
</StackPanel>
</DockPanel>
</DockPanel>
</Grid>
</Window>
</pre>