DialogService Host Window

samples/SampleDialogApp/ViewModels/DialogViewModel.cs

@@ -1,81 +1,98 @@
 using System;
+using Avalonia.Controls;
 using Prism.Commands;
 using Prism.Mvvm;
-using Prism.Regions;
 using Prism.Services.Dialogs;
+using SampleDialogApp.Views;
 
-namespace SampleDialogApp.ViewModels
+namespace SampleDialogApp.ViewModels;
+
+public class DialogViewModel : BindableBase, IDialogAware
 {
-    public class DialogViewModel : BindableBase, IDialogAware
+    private readonly IDialogService _dialogService;
+    private string _customMessage = string.Empty;
+    private string _title = "Notification";
+    private Window? _parentWindow = null;
+
+    public DialogViewModel(IDialogService dialogService)
+    {
+        _dialogService = dialogService;
+
+        // This is a ViewModel of a pop-up dialog,
+        // the Title is pre-binded to Prism.Avalonia's DialogService
+        Title = "I'm a Sample Dialog!";
+    }
+
+    public string Title
+    {
+        get => _title;
+        set => SetProperty(ref _title, value);
+    }
+
+    /// <summary>Gets or sets the optional parent window of this Dialog pop-up.</summary>
+    public Window? ParentWindow
+    {
+        get => _parentWindow;
+        set => SetProperty(ref _parentWindow, value);
+    }
+
+    public DelegateCommand CmdModalDialog => new(() =>
+    {
+        var title = "MessageBox Title Here";
+        var message = "Hello, I am a modal MessageBox window.\n\n" +
+                      $"I {(ParentWindow == null ? "dont" : "do")} have a parent.";
+
+        _dialogService.ShowDialog(
+            ParentWindow,
+            nameof(MessageBoxView),
+            new DialogParameters($"title={title}&message={message}"),
+            r => { });
+    });
+
+    public DelegateCommand<string> CmdResult => new DelegateCommand<string>((param) =>
+    {
+        // None = 0
+        // OK = 1
+        // Cancel = 2
+        // Abort = 3
+        // Retry = 4
+        // Ignore = 5
+        // Yes = 6
+        // No = 7
+        ButtonResult result = ButtonResult.None;
+
+        if (int.TryParse(param, out int intResult))
+            result = (ButtonResult)intResult;
+
+        RaiseRequestClose(new DialogResult(result));
+    });
+
+    public string CustomMessage
+    {
+        get => _customMessage;
+        set => SetProperty(ref _customMessage, value);
+    }
+
+    public event Action<IDialogResult>? RequestClose;
+
+    public virtual bool CanCloseDialog()
+    {
+        // Allow the dialog to close
+        return true;
+    }
+
+    public virtual void OnDialogClosed()
+    {
+        System.Diagnostics.Debug.WriteLine("Detach custom event handlers here, etc.");
+    }
+
+    public void OnDialogOpened(IDialogParameters parameters)
+    {
+        CustomMessage = parameters.GetValue<string>("message");
+    }
+
+    public virtual void RaiseRequestClose(IDialogResult dialogResult)
     {
-        private readonly IDialogService _dialog;
-        private string _customMessage;
-        private string _title = "Notification";
-
-        public DialogViewModel()
-        {
-            // Since this is a basic ShellWindow, there's nothing
-            // to do here.
-            // For enterprise apps, you could register up subscriptions
-            // or other startup background tasks so that they get triggered
-            // on startup, rather than putting them in the DashboardViewModel.
-            //
-            // For example, initiate the pulling of News Feeds, etc.
-
-            Title = "Sample Dialog!";
-        }
-
-        public string Title
-        {
-            get => _title;
-            set => SetProperty(ref _title, value);
-        }
-
-        public DelegateCommand<string> CmdResult => new DelegateCommand<string>((param) =>
-        {
-            // None = 0
-            // OK = 1
-            // Cancel = 2
-            // Abort = 3
-            // Retry = 4
-            // Ignore = 5
-            // Yes = 6
-            // No = 7
-            ButtonResult result = ButtonResult.None;
-
-            if (int.TryParse(param, out int intResult))
-                result = (ButtonResult)intResult;
-
-            RaiseRequestClose(new DialogResult(result));
-        });
-
-        public string CustomMessage
-        {
-            get => _customMessage;
-            set => SetProperty(ref _customMessage, value);
-        }
-
-        public event Action<IDialogResult> RequestClose;
-
-        public virtual bool CanCloseDialog()
-        {
-            // Allow the dialog to close
-            return true;
-        }
-
-        public virtual void OnDialogClosed()
-        {
-            // Detatch custom eventhandlers here, etc.
-        }
-
-        public void OnDialogOpened(IDialogParameters parameters)
-        {
-            CustomMessage = parameters.GetValue<string>("message");
-        }
-
-        public virtual void RaiseRequestClose(IDialogResult dialogResult)
-        {
-            RequestClose?.Invoke(dialogResult);
-        }
+        RequestClose?.Invoke(dialogResult);
     }
 }

samples/SampleDialogApp/ViewModels/MessageBoxViewModel.cs

@@ -1,7 +1,6 @@
 using System;
 using Prism.Commands;
 using Prism.Mvvm;
-using Prism.Regions;
 using Prism.Services.Dialogs;
 
 namespace SampleDialogApp.ViewModels;

samples/SampleDialogApp/Views/DialogView.axaml

@@ -8,26 +8,37 @@
              Height="200" Width="400"
              x:Class="SampleDialogApp.Views.DialogView">
   <StackPanel HorizontalAlignment="Center" Spacing=" 5">
-    <Label Content="{Binding Title}" FontWeight="Bold" />
+    <!--<Label Content="{Binding Title}" FontWeight="Bold" />-->
+
+    <Label Content="Show Modal Dialog:" />
+    <StackPanel Orientation="Horizontal" Spacing="5">
+      <Button Content="Modal from .AXAML.CS" Click="BtnShowModal_Click" />
+      <Button Content="Modal from MVVM" Command="{Binding CmdModalDialog}" />
+    </StackPanel>
 
     <StackPanel Orientation="Horizontal">
       <Label Content="Custom Param:" />
       <Label Content="{Binding CustomMessage}" />
     </StackPanel>
 
-    <StackPanel Orientation="Horizontal" Spacing="5">
-        <Button Content="None" Command="{Binding CmdResult}" CommandParameter="0" />
-        <Button Content="OK" Command="{Binding CmdResult}" CommandParameter="1" />
-        <Button Content="Cancel" Command="{Binding CmdResult}" CommandParameter="2" />
-      </StackPanel>
-      <StackPanel Orientation="Horizontal" Spacing="5">
-        <Button Content="Abort" Command="{Binding CmdResult}" CommandParameter="3" />
-        <Button Content="Retry" Command="{Binding CmdResult}" CommandParameter="4" />
-        <Button Content="Ignore" Command="{Binding CmdResult}" CommandParameter="5" />
-      </StackPanel>
-      <StackPanel Orientation="Horizontal" Spacing="5">
-        <Button Content="Yes" Command="{Binding CmdResult}" CommandParameter="6" />
-        <Button Content="No" Command="{Binding CmdResult}" CommandParameter="7" />
-      </StackPanel>
+    <Grid RowDefinitions="auto,auto,auto" ColumnDefinitions="auto,auto,auto">
+      <Grid.Styles>
+        <Style Selector="Button">
+          <Setter Property="HorizontalAlignment" Value="Stretch" />
+          <Setter Property="Margin" Value="2" />
+        </Style>
+      </Grid.Styles>
+
+      <Button Grid.Row="0" Grid.Column="0" Content="None" Command="{Binding CmdResult}" CommandParameter="0" />
+      <Button Grid.Row="0" Grid.Column="1" Content="OK" Command="{Binding CmdResult}" CommandParameter="1" />
+      <Button Grid.Row="0" Grid.Column="2" Content="Cancel" Command="{Binding CmdResult}" CommandParameter="2" />
+
+      <Button Grid.Row="1" Grid.Column="0" Content="Abort" Command="{Binding CmdResult}" CommandParameter="3" />
+      <Button Grid.Row="1" Grid.Column="1" Content="Retry" Command="{Binding CmdResult}" CommandParameter="4" />
+      <Button Grid.Row="1" Grid.Column="2" Content="Ignore" Command="{Binding CmdResult}" CommandParameter="5" />
+
+      <Button Grid.Row="2" Grid.Column="0" Content="Yes" Command="{Binding CmdResult}" CommandParameter="6" />
+      <Button Grid.Row="2" Grid.Column="1" Content="No" Command="{Binding CmdResult}" CommandParameter="7" />
+    </Grid>
   </StackPanel>
-</UserControl>
+</UserControl>

samples/SampleDialogApp/Views/DialogView.axaml.cs

@@ -1,18 +1,50 @@
 using Avalonia.Controls;
+using Avalonia.Interactivity;
 using Avalonia.Markup.Xaml;
+using Prism.Ioc;
+using Prism.Services.Dialogs;
+using SampleDialogApp.ViewModels;
 
-namespace SampleDialogApp.Views
+namespace SampleDialogApp.Views;
+
+public partial class DialogView : UserControl
 {
-    public partial class DialogView : UserControl
+    public DialogView()
+    {
+        InitializeComponent();
+    }
+
+    protected override void OnInitialized()
     {
-        public DialogView()
+        base.OnInitialized();
+
+        // Pass the parent window to the ViewModel
+        // given that the ViewModel has been binded to this view
+        DialogViewModel? viewModel = this.DataContext as DialogViewModel;
+        if (this.Parent is Window parent &&
+            viewModel is not null)
         {
-            InitializeComponent();
+            viewModel.ParentWindow = parent;
         }
+    }
+
+    private void InitializeComponent()
+    {
+        AvaloniaXamlLoader.Load(this);
+    }
+
+    private void BtnShowModal_Click(object sender, RoutedEventArgs args)
+    {
+        var dialogSvc = ContainerLocator.Current.Resolve<IDialogService>();
+
+        var title = "MessageBox Title Here";
+        var message = "Hello, I am a simple modal MessageBox with an OK button.\n\n" +
+                      "I've been called by the `.axaml.cs` UserControl.";
 
-        ////private void InitializeComponent()
-        ////{
-        ////    AvaloniaXamlLoader.Load(this);
-        ////}
+        dialogSvc.ShowDialog(
+            this.Parent as Window,
+            nameof(MessageBoxView),
+            new DialogParameters($"title={title}&message={message}"),
+            r => { });
     }
 }

src/Prism.Avalonia/Services/Dialogs/DialogService.cs

@@ -75,7 +75,13 @@ public void ShowDialog(string name, IDialogParameters parameters, Action<IDialog
             ShowDialogInternal(name, parameters, callback, true, windowName);
         }
 
-        void ShowDialogInternal(string name, IDialogParameters parameters, Action<IDialogResult> callback, bool isModal, string windowName = null)
+        /// <inheritdoc/>
+        public void ShowDialog(Window owner, string name, IDialogParameters parameters, Action<IDialogResult> callback)
+        {
+            ShowDialogInternal(name, parameters, callback, true, parentWindow: owner);
+        }
+
+        private void ShowDialogInternal(string name, IDialogParameters parameters, Action<IDialogResult> callback, bool isModal, string windowName = null, Window parentWindow = null)
         {
             if (parameters == null)
                 parameters = new DialogParameters();
@@ -84,24 +90,29 @@ void ShowDialogInternal(string name, IDialogParameters parameters, Action<IDialo
             ConfigureDialogWindowEvents(dialogWindow, callback);
             ConfigureDialogWindowContent(name, dialogWindow, parameters);
 
-            ShowDialogWindow(dialogWindow, isModal);
+            ShowDialogWindow(dialogWindow, isModal, parentWindow);
         }
 
         /// <summary>
         /// Shows the dialog window.
         /// </summary>
         /// <param name="dialogWindow">The dialog window to show.</param>
         /// <param name="isModal">If true; dialog is shown as a modal</param>
-        protected virtual void ShowDialogWindow(IDialogWindow dialogWindow, bool isModal)
+        /// <param name="owner">Optional host window of the dialog.</param>
+        protected virtual void ShowDialogWindow(IDialogWindow dialogWindow, bool isModal, Window owner = null)
         {
-            if (isModal && 
+            if (isModal &&
                 Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime deskLifetime)
             {
                 // Ref:
                 //  - https://docs.avaloniaui.net/docs/controls/window#show-a-window-as-a-dialog
                 //  - https://github.com/AvaloniaUI/Avalonia/discussions/7924
                 // (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktopLifetime)
-                dialogWindow.ShowDialog(deskLifetime.MainWindow);
+
+                if (owner != null)
+                    dialogWindow.ShowDialog(owner);
+                else
+                    dialogWindow.ShowDialog(deskLifetime.MainWindow);
             }
             else
             {
@@ -149,7 +160,7 @@ protected virtual void ConfigureDialogWindowContent(string dialogName, IDialogWi
         /// </summary>
         /// <param name="dialogWindow">The hosting window.</param>
         /// <param name="callback">The action to perform when the dialog is closed.</param>
-        protected virtual void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, Action<IDialogResult> callback)
+        protected virtual void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, Action<IDialogResult>? callback)
         {
             Action<IDialogResult> requestCloseHandler = null;
             requestCloseHandler = (o) =>
@@ -167,6 +178,7 @@ protected virtual void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, A
                 dialogWindow.Opened -= loadedHandler;
                 dialogWindow.GetDialogViewModel().RequestClose += requestCloseHandler;
             };
+
             dialogWindow.Opened += loadedHandler;
             //// WPF: dialogWindow.Loaded += loadedHandler;
 
@@ -176,6 +188,7 @@ protected virtual void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, A
                 if (!dialogWindow.GetDialogViewModel().CanCloseDialog())
                     e.Cancel = true;
             };
+
             dialogWindow.Closing += closingHandler;
 
             EventHandler closedHandler = null;
@@ -195,6 +208,7 @@ protected virtual void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, A
                 dialogWindow.DataContext = null;
                 dialogWindow.Content = null;
             };
+
             dialogWindow.Closed += closedHandler;
         }