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WpfExtensions

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This project comes from some scattered works I did while working on Wpf development, and is a supplement to existing Mvvm frameworks. They don't solve any major problems, they just provide some syntactic sugar and let people write a few lines of code less. Its services are not limited to Wpf development, other similar Xaml frameworks, such as Uwp, Maui, etc. should also be able to use, but I has never tested on other frameworks.

The project is structured as follows:

• WpfExtensions.Xaml：A number of MarkupExtensions are provided to simplify Xaml development.
• WpfExtensions.Binding：To simplify the code for property dependency updates, a function similar to the one in Vue.js for computed-property is provided.
• WpfExtensions.Infrastructure：Some scattered features, when the time is ripe, will be separated out and released as separate modules.

NuGet

Package	NuGet
WpfExtensions.Xaml
WpfExtensions.Binding

1. WpfExtensions.Binding

Brings some of the functionality of the Reactivity module from Vue3 into Wpf.

The term "observable" as used in the following documentation refers to objects that implement INotifyPropertyChanged or INotifyCollectionChanged.

1.1 Watch

Subscribe to an observable expression and trigger a callback function when its value changes.

// See the source code for more overloads, whose signatures are consistent with vue3's `watch()`, and the vue3 documentation for examples.
Reactivity.Default.Watch(() => Width * Height, area => Debug.WriteLine(area));

1.2 WatchDeep

Deep traversal subscribes to an observable object and triggers a callback function when its properties, or the properties of its properties, change.

// `path` will print out the path to the specific property that was changed.
Reactivity.Default.WatchDeep(obj, path => Debug.WriteLine(path))

1.3 Computed

Computed property that is an instance method of the BindableBase base class.

public class ViewModel : BindableBase {
    // Can be bound to xaml to automatically notify Area changes when Width or Height changes.
    public double Area => Computed(() => Width * Height);
}

2. WpfExtensions.Xaml

0. *New CommandExtension

• View (XAML):

<Element Command={markup:Command Execute} />
<Element Command={markup:Command ExecuteWithArgumentAsync, CanExecute}
         CommandParameter={Binding Argument} />

• View Model (*.cs):

class ViewModel
{
    public void Execute() {}

    public void ExecuteWithArgument(string arg) {}

    // The `Execute` method supports async, and its default `Can Execute` method will disable the command when it is busy.

    public Task ExecuteAsync() => Task.Completed;

    public Task ExecuteWithArgumentAsync(string arg) => Task.Completed;

    // The `Can Execute` method does not support async.

    public bool CanExecute() => true;

    public bool CanExecuteWithArgument(string arg) => true;
}

1. ComposeExtension

Combine multiple Converters into one pipeline.

<TextBlock Visibility="{Binding DescriptionText, Converter={markup:Compose
                       {StaticResource IsNullOrEmptyOperator},
                       {StaticResource NotConverter},
                       {StaticResource BooleanToVisibilityConverter}}}"
           Text="{Binding DescriptionText}" />

2. IfExtension

Using the Conditional expression in XAML.

<Button Command="{markup:If {Binding BoolProperty},
                            {Binding OkCommand},
                            {Binding CancelCommand}}" />

<UserControl>
    <markup:If Condition="{Binding IsLoading}">
        <markup:If.True>
            <views:LoadingView />
        </markup:If.True>
        <markup:If.False>
            <views:LoadedView />
        </markup:If.False>
    </markup:If>
</UserControl>

3. SwitchExtension

Using the Switch expression in XAML.

<Image Source="{markup:Switch {Binding FileType},
                              {Case {x:Static res:FileType.Music}, {StaticResource MusicIcon}},
                              {Case {x:Static res:FileType.Video}, {StaticResource VideoIcon}},
                              {Case {x:Static res:FileType.Picture}, {StaticResource PictureIcon}},
                              ...
                              {Case {StaticResource UnknownFileIcon}}}" />

<UserControl>
    <Switch To="{Binding SelectedViewName}">
        <Case Label="View1">
            <views:View1 />
        </Case>
        <Case Label="{x:Static res:Views.View2}">
            <views:View2 />
        </Case>
        <Case>
            <views:View404 />
        </Case>
    </Switch>
</UserControl>

4. I18nExtension

Dynamically switch the culture resource without restarting the app.

<TextBlock Text="{markup:I18n {x:Static languages:UiStrings.MainWindow_Title}}" />
<TextBlock Text="{markup:I18nString {x:Static languages:UiStrings.SayHello}, {Binding Username}}" />
<TextBlock Text="{markup:I18nString {x:Static languages:UiStrings.StringFormat},
                                    {Binding Arg0},
                                    {Binding Arg1},
                                    ...,
                                    {Binding Arg15}}" />

5. StylesExtension (In Progress)

<Button Style="{markup:Styles {StaticResource FlatButtonStyle},
                              {StaticResource AnimationStyle},
                              ...}" />