UWP App using MVVM: Registration of feature view on main view

Question

I am new to c# and uwp apps. And this is my first try with MVVM. I have the following program design and go according to the schema of the FDD. MVVM App-Design

I would like to achieve:

Registration of the ViewFeature.xaml on ViewMain.xaml
communication between features.

I have the following simple Approach: Add the ViewFeature.xaml to ViewMain.xaml by Code, which unfortunately does not work at the moment.

View Registration:

MainView.xaml

<Page
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:viewModels="using:Client.ViewModel"
x:Class="Client.View.ViewMain"
mc:Ignorable="d">

<Grid x:Name="ContentGrid" RequestedTheme="Light">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="Auto"/>
    </Grid.ColumnDefinitions>
    <StackPanel Name="FeatureLeft"      Orientation="Horizontal" Grid.Column="0"/>
    <StackPanel Name="FeatureCenter"    Orientation="Horizontal" Grid.Column="1"/>
    <StackPanel Name="FeatureRight"     Orientation="Horizontal" Grid.Column="2"/>
</Grid>
</Page>

ViewMain.xaml.cs

public sealed partial class ViewMain : Page
{

    public ViewModelMain viewModelMain;

    public ViewMain()
    {           
        this.InitializeComponent();
        viewModelMain = new ViewModelMain();
        viewModelMain.RegisterFeatures(this);        
    }
}

ViewModelMain.cs

public class ViewModelMain: NotificationBase
{
    public ModelMain model;
    public ViewModelMain()
    {
        model = new ModelMain();
        _Features = model.LoadFeatures();
    }

    public void RegisterFeatures(Page p)
    {
        foreach (var feature in _Features)
        {
            feature.AddToView(p);
        }
    }

    ObservableCollection<IViewFeature> _Features = new ObservableCollection<IViewFeature>();
    public ObservableCollection<IViewFeature> Features {
        get { return _Features; }
        set { SetProperty(ref _Features, value); }
    }

}

ModelMain.cs

public class ModelMain
{

    public ObservableCollection<IViewFeature> FeatureList;


    public ObservableCollection<IViewFeature> LoadFeatures()
    {
        FeatureList = new ObservableCollection<IViewFeature>();
        IViewFeature galleryFeature = new Gallery.View.ViewGallery();
        FeatureList.Add(galleryFeature);

        return FeatureList;
    }

}

Each Feature knows his own position on the ViewMain.xml and implements in the ViewFeaure.xaml.cs the following method to register its own ViewFeature.xaml on the ViewMain.xaml

public void AddToView( Page p)
    {
        StackPanel target = (StackPanel)p.FindName("FeatureLeft");
        target.Children.Add(this);
    }

Any professional approach or help will be appreciated.

@user1777136 The main view is blank and there is no error message. There should be a button, which opens the detail view of an image gallery. — Calid, Jul 28 '17 at 19:31

score 0 · Accepted Answer · answered Jul 28 '17 at 19:56

0

The problem is in this line.

target.Children.Add(this);

should be

target.Children.Add(this as UIElement);

However, I would still want to know how a professional approach to feature-based applications might look in the context of feature-driven development (FDD).

answered Jul 28 '17 at 19:56

Calid

1
3

Your code looks reasonable. What I would shy away from is to "hard code" the `StackPanel` inside the `AddToView` method. The binding mechanism can get you out of this. MVVM relies heavily on bindings to decouple code from the view. So e.g. `` would allow you to remove the entire `RegisterFeatures` and `AddToView` methods. – user1777136 Jul 30 '17 at 18:52

UWP App using MVVM: Registration of feature view on main view

1 Answers1