CODEWITHSUNDEEP
c#mvvmuwp
stef morren
stef morren

Reputation: 289

[UWP][MVVM] Navigate in a frame in a window

I'm building an UWP app with a navigationview. When I click on my navigation item I want to change my frame. It's really easy to do this without MVVM but I prefer a solution with MVVM.

enter image description here

My Frame is "ContentFrame". Now I want to use a navigationservice. The classic way to do this is:

 public class NavigationService : INavigationService
{
    public void NavigateTo(Type viewType)
    {
        Frame rootFrame = Window.Current.Content as Frame;
        rootFrame.Navigate(viewType);
    }

    public void NavigateBack()
    {
        Frame rootFrame = Window.Current.Content as Frame;
        rootFrame.GoBack();
    }
}

But for my use case the "Window.Current.Content" should be replaced with the Frame from my HomePage. I've no idea how I can access this through MVVM.

My project is on a public git: https://github.com/stefmorren/AutoClicker/tree/Devel

You can do a push request if it's easier.

Upvotes: 1

Views: 3265

Answers (1)

Martin Zikmund
Martin Zikmund

Reputation: 39072

First add a public property of type Frame to your HomePage:

public Frame NavigationFrame => ContentFrame;

Now, your HomePage is currently inside a root Frame. To get to it, you will have to use it's Content property:

public class NavigationService : INavigationService
{
    public void NavigateTo(Type viewType)
    {
        var rootFrame = Window.Current.Content as Frame;
        var homePage = rootFrame.Content as HomePage;
        homePage.NavigationFrame.Navigate(viewType);
    }

    public void NavigateBack()
    {
        var rootFrame = Window.Current.Content as Frame;
        var homePage = rootFrame.Content as HomePage;
        homePage.NavigationFrame.GoBack();
    }
}

Even simpler solution

To simplify this a bit more, you could even remove the rootFrame altogether. In App.xaml.cs you have to update your code to create the HomePage directly:

protected override void OnLaunched(LaunchActivatedEventArgs e)
{
    HomePage page = Window.Current.Content as HomePage;

    // Do not repeat app initialization when the Window already has content,
    // just ensure that the window is active
    if (page == null)
    {
        page = new HomePage();
        Window.Current.Content = page;
    }

    if (e.PrelaunchActivated == false)
    {
        // Ensure the current window is active
        Window.Current.Activate();
    }
}

And you would now use the following to access the NavigationFrame property:

public class NavigationService : INavigationService
{
    public void NavigateTo(Type viewType)
    {
        var homePage = Window.Current.Content as HomePage;
        homePage.NavigationFrame.Navigate(viewType);
    }

    public void NavigateBack()
    {
        var homePage = Window.Current.Content as HomePage;
        homePage.NavigationFrame.GoBack();
    }
}

Now HomePage is directly the Content of your Window, so we can access it via Window.Current.Content.

Upvotes: 5

Related Questions