Ndtyjky

On initialization of main window i set DataContext to usercontrol and on this usercontrol i have an event which suppose to change datacontext of main window to another usercontrol but nothing happens.

Here is xaml for main window:

</Window.Resources>

<Grid>

    <ContentControl Content="{Binding}" Width="auto" Height="auto" />

</Grid>

Here is C# for main window:

public MainWindow()

    {

        InitializeComponent();

        DataContext = new LogInViewModel();

    }

Here is xaml for LogInUserControl:

<Grid>

    <Grid.ColumnDefinitions>

        <ColumnDefinition/>

        <ColumnDefinition/>

        <ColumnDefinition/>

    </Grid.ColumnDefinitions>

    <Grid.RowDefinitions>

        <RowDefinition/>

        <RowDefinition/>

        <RowDefinition/>

    </Grid.RowDefinitions>

    <StackPanel Grid.Column="1" Grid.Row="1">

        <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Width="250">

            <StackPanel Width="125">

                <TextBlock Text="Email:" Margin="5,0,5,0" Width="auto"/>

            </StackPanel>

            <StackPanel Width="125">

                <TextBlock Text="Password:" Margin="5,0,0,0" Width="auto"/>

            </StackPanel>

        </StackPanel>

        <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">

        <TextBox Margin="5,0,5,0" HorizontalAlignment="Center" Height="23" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>

        <PasswordBox Margin="0,0,0,5" HorizontalAlignment="Center" Height="23" VerticalAlignment="Top" Width="120"/>

        </StackPanel>

        <Button Content="Log In" Margin="0,0,0,5" HorizontalAlignment="Center" VerticalAlignment="Top" Width="75"/>

    </StackPanel>

    <Grid Grid.Column="1" Grid.Row="1">

        <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">

        <TextBlock Text="don't have account yet ?" HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="5"/>

        <TextBlock Name="TBSignUp" Text="Sign Up" HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="5" PreviewMouseLeftButtonDown="TextBlock_PreviewMouseLeftButtonDown" PreviewMouseLeftButtonUp="TextBlock_PreviewMouseLeftButtonUp" Foreground="#FF0B36F5"/>

        </StackPanel>

    </Grid>

</Grid>

and here is C# for LogInUserControl:

public partial class LogInView : UserControl

{

    string BlackForeground = "#FF000000" ;

    string OriginalForeground = "#FF0B36F5";

    public LogInView()

    {

        InitializeComponent();

    }



    private void TextBlock_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)

    {

        TBSignUp.Foreground = new SolidColorBrush((Color)ColorConverter.ConvertFromString(OriginalForeground));

        DataContext = new RegisterView();

    }



    private void TextBlock_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)

    {

        TBSignUp.Foreground = new SolidColorBrush((Color)ColorConverter.ConvertFromString(BlackForeground));

    }

}

In WPF you can get a shell window from anywhere:

Application.Current.MainWindow; // this is your shell window

Application.Current.MainWindow.DataContext; // this is your shell window data context

If you want to change the view of your user control or its data context, then I suggest doing it with the data context of the parent window.

If you want to change the interface, you can use Content Control as container by simply changing its Content property to all of your user controls.

As a result, each user control will have its own view and data context, and it will be independent of the other.

You need to set it on App.xaml.cs.

App.xaml.cs:

public class App : Application

{

    protected override void OnStartup(StartupEventArgs e)

    {

         MainWindow window=new MainWindow();

         LogInViewModel vm=new LogInViewModel(); // You need to set DataContext...

         window.DataContext=vm; // ...before showing up the window.

         window.Show();

    }

 }

In the ViewModel patterns that I found from research, usage is before DataContext, after Show();.

I hope that solves your problem.