Introduction

Provides the ability to show various dialogs and child windows in a DI injectable application dialog service ready to plug into MVVM AvaloniaUI applications.

The general idea is to make it as simple as possible to handle all the basics of using dialogs with as few assumptions as possible whilst also providing a feature rich experience.

More or less everything is replaceable, extendable, customisable.

GitHub Pages Site

https://jamsoft.github.io/JamSoft.AvaloniaUI.Dialogs/

Installation

dotnet add package JamSoft.AvaloniaUI.Dialogs --version 1.0.0

Install-Package JamSoft.AvaloniaUI.Dialogs -Version 1.0.0

<PackageReference Include="JamSoft.AvaloniaUI.Dialogs" Version="1.0.0" />

paket add JamSoft.AvaloniaUI.Dialogs --version 1.0.0

Import Styles

All Defaults

<Application.Styles>
    <FluentTheme Mode="Dark"/>
    <StyleInclude Source="avares://JamSoft.AvaloniaUI.Dialogs/Themes/Default.axaml"/>
</Application.Styles>

Individual

<Application.Styles>
    <FluentTheme Mode="Dark"/>
    <StyleInclude Source="avares://JamSoft.AvaloniaUI.Dialogs/Themes/ChildStyle.axaml"/>
    <StyleInclude Source="avares://JamSoft.AvaloniaUI.Dialogs/Themes/ModalStyle.axaml"/>
</Application.Styles>

Custom Styling

Since we are using plain old Window objects, basic styling properties like Background colors will be inherited from your own applications default Window style, such as:

<Style Selector="Window">
    <Setter Property="Background" Value="#333333" />
</Style>

Creating Instances

IDialogService dialogService = DialogServiceFactory.Create(new DialogServiceConfiguration({
    ApplicationName = "Dialog Sample App", 
    UseApplicationNameInTitle = true,
    ViewsAssemblyName = Assembly.GetExecutingAssembly().GetName().Name
});

Registration Example Using Splat DI

public static void Main(string[] args)
{
    RegisterDependencies();
    
    BuildAvaloniaApp()
        .StartWithClassicDesktopLifetime(args);
}

private static void RegisterDependencies() =>
    BootStrapper.Register(Locator.CurrentMutable, Locator.Current);
        

Registering the Service – Bootstrapper.cs

public class BootStrapper
{
    public static void Register(IMutableDependencyResolver services, IReadonlyDependencyResolver resolver)
    {
        services.RegisterLazySingleton(() => DialogServiceFactory.Create(new DialogServiceConfiguration
        {
            ApplicationName = "Dialog Sample App", 
            UseApplicationNameInTitle = true,
            ViewsAssemblyName = "JamSoft.AvaloniaUI.Dialogs.Sample"
        }));
        
        services.Register(() => new MainWindowViewModel(resolver.GetService<IDialogService>()));
        services.Register(() => new MyDialogViewModel());
        services.Register(() => new MyChildViewModel());
    }
}        

Usage

File Paths

Now that we have this setup and registered, we can make use of the service from view models like this. First add it as a constructor parameter.

private readonly IDialogService _dialogService;

public MainWindowViewModel(IDialogService dialogService)
{
    _dialogService = dialogService;
}
...

Open Any File

string path = await _dialogService.OpenFile("Open Any File");

Open A Specific File Type

string path = await _dialogService.OpenFile("Open Word File", new List<FileDialogFilter>
{
    new()
    {
        Name = "Docx Word File", 
        Extensions = new List<string> { "docx" }
    }
});

You can also make use of the built in CommonFilters helper class.

string path = await _dialogService.OpenFile("Open Word File", new List<FileDialogFilter>
{
    CommonFilters.WordFilter
});

Open Multiple Files

string[] paths = await _dialogService.OpenFiles("Open Multiple Files");

Save Any Path

string path = await _dialogService.SaveFile("Save Any File");

Save To Your Custom File Type

string path = await _dialogService.SaveFile("Save New MyApp Project", new List<FileDialogFilter>
{
    new()
    {
        Name = "MyApp Project", 
        Extensions = new List<string> { "myappext" }
    }
});

Usage – Dialogs

There are two base view model classes already baked in for ease of use of the library. These are provided as defaults and a starting point. Create a suitable view model and inherit from either DialogViewModel or ChildWindowViewModel as base class.

Show Dialog

_dialogService.ShowDialog(Locator.Current.GetService<MyDialogViewModel>(), DialogCallback);

private void DialogCallback(MyDialogViewModel obj)
{
    Message = obj.DialogMessage;
}

Custom Button Text

private void ShowCustomizedDialogCommandExecuted()
{
    var vm = Locator.Current.GetService<MyDialogViewModel>();
    vm.AcceptCommandText = "Accept";
    vm.CancelCommandText = "Oh No!";
    
    _dialogService.ShowDialog(vm, DialogCallback);
}

Alternate View

private void ShowCustomizedDialogCommandExecuted()
{
    var vm = Locator.Current.GetService<MyDialogViewModel>();
    vm.AcceptCommandText = "Accept";
    vm.CancelCommandText = "Oh No!";
    
    _dialogService.ShowDialog(new MyAlternateDialogView(), vm, DialogCallback);
}

Default Key Mapping

The dialog buttons are also associated with their keyboard inputs.

<Window.KeyBindings>
    <KeyBinding Gesture="Escape" Command="{Binding CancelCommand}" />
    <KeyBinding Gesture="Enter" Command="{Binding AcceptCommand}" />
</Window.KeyBindings>

Show Child Window

private void ShowChildWindowCommandExecuted()
{
    var vm = Locator.Current.GetService<MyChildViewModel>();

    // these values could be stored in user settings and loaded at runtime etc.
    vm.RequestedLeft = 50;
    vm.RequestedTop = 50;
    vm.RequestedHeight = 600;
    vm.RequestedWidth = 800;
    vm.ChildMessage = "Child Message Value";
    vm.ChildWindowTitle = "My Child Window Title";
    
    _dialogService.ShowChildWindow(vm, model =>
    {
        Message = $"Child Closed - {model.ChildMessage}";
    });
}

The child windows are draggable and also update these properties in real-time. This means that your application can easily restore child window positions between application runs by storing these values.

Show Child Window – Alternate View Parameter

private void ShowChildWindowCommandExecuted()
{
    var vm = Locator.Current.GetService<MyChildViewModel>();

    ...
    
    _dialogService.ShowChildWindow(new MyAlternateChildView(), vm, model =>
    {
        Message = $"Child Closed - {model.ChildMessage}";
    });
}

Saving & Restoring Window Positions

First you need a mechanism to store positions as set by the user moving things around.

public class MyUserSettings : SettingsBase<MyUserSettings>
{
    public double Left { get; set; } = 50;
    public double Top { get; set; } = 50;
    public double Height { get; set; } = 600;
    public double Width { get; set; } = 800;
}

SettingsBase<T> can be found in the JamSoft.Helpers package https://github.com/jamsoft/JamSoft.Helpers

Install-Package JamSoft.Helpers

Then in your view model you can listen for the RequestCloseDialog event and respond accordingly by storing the settings in the OnRequestCloseDialog method.

public class MyChildWindowViewModel : ChildWindowViewModel
{
    private string? _childMessage;
    
    public MyChildWindowViewModel()
    {
        RequestCloseDialog += OnRequestCloseDialog;
    }
    
    public string? ChildMessage
    {
        get => _childMessage;
        set => RaiseAndSetIfChanged(ref _childMessage, value);
    }
    
    private void OnRequestCloseDialog(object? sender, RequestCloseDialogEventArgs e)
    {
        MyUserSettings.Instance.Top = RequestedTop;
        MyUserSettings.Instance.Left = RequestedLeft;
        MyUserSettings.Instance.Width = RequestedWidth;
        MyUserSettings.Instance.Height = RequestedHeight;
        
        RequestCloseDialog -= OnRequestCloseDialog;
    }
}

The next time this view model is requested by the user you can then restore these values.

vm.RequestedLeft = MyUserSettings.Instance.Left;
vm.RequestedTop = MyUserSettings.Instance.Top;
vm.RequestedHeight = MyUserSettings.Instance.Height;
vm.RequestedWidth = MyUserSettings.Instance.Width;

vm.ChildWindowTitle = "My Custom Child Window Title Auto Find";

_dialogService.ShowChildWindow(vm, model =>
{
    Message = $"Child Remember Position Closed - {model.GetType()}";
});

See the Sample Application for a complete implementation example and guidance.

Application Styles

You can easily target elements of the dialogs via their names and types, such as:

<Application>
    <Application.Styles>        
        <Style Selector="Button.CloseChildButton:pointerover /template/ Border">
                <Setter Property="Background" Value="#c42b1c" />
        </Style>
        
        <Style Selector="DockPanel#ChromeDockPanel">
                <Setter Property="Height" Value="32"/>
                <Setter Property="Background" Value="#000000"/>
        </Style>
        
        <Style Selector="TextBlock#ChromeDockPanelTitle">
                <Setter Property="FontSize" Value="12"/>
                <Setter Property="VerticalAlignment" Value="Center" />
                <Setter Property="Margin" Value="10,0"/>
        </Style>        
    </Application.Styles>
</Application>