CODEWITHSUNDEEP
c#xamarinmvvmuwpmvvmcross
JKL
JKL

Reputation: 1070

Where does this variable come from? MVVMcross UWP framework example

I have downloaded an example from the MVVMcross framework which can be found here. When I build the UWP project it compiles and runs without any errors.

Now I am trying to remake the UWP project and I face a problem which is located in the following file: XPlatformMenus/XPlatformMenus.UWP/Views/Home/HomeView.xaml.cs.

At line 11 and 12 the class is calling a return of base.Viewmodel. Question: Where is this property comming from?

My thinking process:

From my understandings the application is trying to return a property named ViewModel of the HomeViewModel class.

But when you check the HomeViewModel class: XPlatformMenus/XPlatformMenus.Core/ViewModels/Home/HomeViewModel.cs (located in different project, references are made) there is no property ViewModel.

Well the HomeViewModel inherits from BaseViewModel: XPlatformMenus/XPlatformMenus.Core/ViewModels/Base/BaseViewModel.cs but there is neither a property called ViewModel. BaseViewModel inherits from MvxViewModel so that's where it must be comming from! Well no, I view the MvxViewModel class with Visual Studio I receive this from metadata: 

namespace MvvmCross.Core.ViewModels {

    public abstract class MvxViewModel : MvxNavigatingObject, IMvxViewModel
    {
        protected MvxViewModel();

        public MvxRequestedBy RequestedBy { get; set; }

        public void Init(IMvxBundle parameters);
        public void ReloadState(IMvxBundle state);
        public void SaveState(IMvxBundle state);
        public virtual void Start();
        protected virtual void InitFromBundle(IMvxBundle parameters);
        protected virtual void ReloadFromBundle(IMvxBundle state);
        protected virtual void SaveStateToBundle(IMvxBundle bundle);
    }
}

This neither has a ViewModel property... When I use the "Go to definition" function on the ViewModel property in Visual Studio she leads me to MvxWindowsPage: 

using MvvmCross.Core.ViewModels;
using MvvmCross.Core.Views;
using MvvmCross.Platform.Core;
using MvvmCross.WindowsUWP.Views.Suspension;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

namespace MvvmCross.WindowsUWP.Views
{
    public class MvxWindowsPage : Page, IMvxWindowsView, IMvxView, IMvxDataConsumer
    {
        public MvxWindowsPage();

        public IMvxWindowsFrame WrappedFrame { get; }
        public IMvxViewModel ViewModel { get; set; }
        protected IMvxSuspensionManager SuspensionManager { get; }

        public void ClearBackStack();
        protected virtual IMvxBundle LoadStateBundle(NavigationEventArgs e);
        protected override void OnNavigatedFrom(NavigationEventArgs e);
        protected override void OnNavigatedTo(NavigationEventArgs e);
        protected virtual void SaveStateBundle(NavigationEventArgs navigationEventArgs, IMvxBundle bundle);
    }
}

Which, indeed, has a property ViewModel. But I dont get how the HomeView knows about this class because I dont see where it gets set in the inherit path..

Upvotes: 0

Views: 259

Answers (1)

dvorn
dvorn

Reputation: 3147

base.ViewModel refers to the class HomeView (in which it is used) which derives from BaseView.

In HomeView.xaml:

<local:BaseView 
x:Class="XPlatformMenus.UWP.Views.HomeView"

Upvotes: 2

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