Make some things observable

src/modules/cmdpal/Microsoft.CmdPal.Common/Messages/GetHwndMessage.cs

@@ -0,0 +1,10 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.CmdPal.Common.Messages;
+
+public partial class GetHwndMessage
+{
+    public nint Hwnd { get; set; } = 0;
+}

src/modules/cmdpal/Microsoft.CmdPal.Core.ViewModels/ParametersViewModels.cs

@@ -4,6 +4,7 @@
 
 using System.Collections.ObjectModel;
 using CommunityToolkit.Mvvm.Messaging;
+using Microsoft.CmdPal.Common.Messages;
 using Microsoft.CmdPal.Core.ViewModels.Messages;
 using Microsoft.CmdPal.Core.ViewModels.Models;
 using Microsoft.CommandPalette.Extensions;
@@ -17,15 +18,51 @@ namespace Microsoft.CmdPal.Core.ViewModels;
 
 public abstract partial class ParameterRunViewModel : ExtensionObjectViewModel
 {
+    private ExtensionObject<IParameterRun> _model;
+
     internal InitializedState Initialized { get; set; } = InitializedState.Uninitialized;
 
     protected bool IsInitialized => IsInErrorState || Initialized.HasFlag(InitializedState.Initialized);
 
     public bool IsInErrorState => Initialized.HasFlag(InitializedState.Error);
 
-    internal ParameterRunViewModel(WeakReference<IPageContext> context)
+    internal ParameterRunViewModel(IParameterRun model, WeakReference<IPageContext> context)
         : base(context)
     {
+        _model = new(model);
+    }
+
+    public override void InitializeProperties()
+    {
+        if (IsInitialized)
+        {
+            return;
+        }
+
+        var model = _model.Unsafe;
+        if (model == null)
+        {
+            return;
+        }
+
+        model.PropChanged += Model_PropChanged;
+    }
+
+    private void Model_PropChanged(object sender, IPropChangedEventArgs args)
+    {
+        try
+        {
+            FetchProperty(args.PropertyName);
+        }
+        catch (Exception ex)
+        {
+            ShowException(ex);
+        }
+    }
+
+    protected virtual void FetchProperty(string propertyName)
+    {
+        // Override in derived classes
     }
 }
 
@@ -36,7 +73,7 @@ public partial class LabelRunViewModel : ParameterRunViewModel
     public string Text { get; set; } = string.Empty;
 
     public LabelRunViewModel(ILabelRun labelRun, WeakReference<IPageContext> context)
-        : base(context)
+        : base(labelRun, context)
     {
         _model = new(labelRun);
     }
@@ -70,7 +107,7 @@ public partial class ParameterValueRunViewModel : ParameterRunViewModel
     public bool NeedsValue { get; set; }
 
     public ParameterValueRunViewModel(IParameterValueRun valueRun, WeakReference<IPageContext> context)
-        : base(context)
+        : base(valueRun, context)
     {
         _model = new(valueRun);
     }
@@ -147,18 +184,31 @@ public partial class StringParameterRunViewModel : ParameterValueRunViewModel
     }
 }
 
-public partial class CommandParameterRunViewModel : ParameterValueRunViewModel
+public partial class CommandParameterRunViewModel : ParameterValueRunViewModel, IDisposable
 {
     private ExtensionObject<ICommandParameterRun> _model;
 
+    private ListViewModel? _listViewModel;
+    private CommandViewModel? _commandViewModel;
+    private AppExtensionHost _extensionHost;
+
     public string DisplayText { get; set; } = string.Empty;
 
     public IconInfoViewModel Icon { get; set; } = new(null);
 
-    public CommandParameterRunViewModel(ICommandParameterRun commandRun, WeakReference<IPageContext> context)
+    public string ButtonLabel => !string.IsNullOrEmpty(DisplayText) ? DisplayText : string.Empty;
+
+    public string SearchBoxText
+    {
+        get => GetSearchText();
+        set => SetSearchText(value);
+    }
+
+    public CommandParameterRunViewModel(ICommandParameterRun commandRun, WeakReference<IPageContext> context, AppExtensionHost extensionHost)
         : base(commandRun, context)
     {
         _model = new(commandRun);
+        _extensionHost = extensionHost;
     }
 
     public override void InitializeProperties()
@@ -182,9 +232,71 @@ public partial class CommandParameterRunViewModel : ParameterValueRunViewModel
             Icon.InitializeProperties();
         }
 
+        GetHwndMessage msg = new();
+        WeakReferenceMessenger.Default.Send(msg);
+        var command = commandRun.GetSelectValueCommand((ulong)msg.Hwnd);
+        if (command == null)
+        {
+        }
+        else if (command is IListPage list)
+        {
+            if (PageContext.TryGetTarget(out var pageContext))
+            {
+                _listViewModel = new ListViewModel(list, pageContext.Scheduler, _extensionHost);
+                _listViewModel.InitializeProperties();
+            }
+        }
+        else if (command is IInvokableCommand invokable)
+        {
+            _commandViewModel = new CommandViewModel(invokable, this.PageContext);
+            _commandViewModel.InitializeProperties();
+        }
+
         UpdateProperty(nameof(DisplayText));
         UpdateProperty(nameof(Icon));
     }
+
+    protected override void FetchProperty(string propertyName)
+    {
+        var model = this._model.Unsafe;
+        if (model is null)
+        {
+            return; // throw?
+        }
+
+        switch (propertyName)
+        {
+            case nameof(ICommandParameterRun.DisplayText):
+                DisplayText = model.DisplayText;
+                break;
+            case nameof(ICommandParameterRun.Icon):
+                Icon = new(model.Icon);
+                if (Icon is not null)
+                {
+                    Icon.InitializeProperties();
+                }
+
+                break;
+        }
+
+        UpdateProperty(propertyName);
+    }
+
+    private string GetSearchText()
+    {
+        return _listViewModel?.SearchText ?? string.Empty;
+    }
+
+    private void SetSearchText(string value)
+    {
+        _listViewModel?.SearchTextBox = value;
+    }
+
+    public void Dispose()
+    {
+        GC.SuppressFinalize(this);
+        _listViewModel?.Dispose();
+    }
 }
 
 public partial class ParametersPageViewModel : PageViewModel, IDisposable
@@ -257,7 +369,7 @@ public partial class ParametersPageViewModel : PageViewModel, IDisposable
                 {
                     ILabelRun labelRun => new LabelRunViewModel(labelRun, PageContext),
                     IStringParameterRun stringRun => new StringParameterRunViewModel(stringRun, PageContext),
-                    ICommandParameterRun commandRun => new CommandParameterRunViewModel(commandRun, PageContext),
+                    ICommandParameterRun commandRun => new CommandParameterRunViewModel(commandRun, PageContext, this.ExtensionHost),
                     _ => null,
                 };
                 if (itemVm != null)

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/SearchBar.xaml

@@ -42,6 +42,19 @@
                     Style="{StaticResource SearchTextBoxStyle}"
                     Text="{x:Bind Text, Mode=TwoWay}" />
             </DataTemplate>
+            <DataTemplate x:Key="ListParamTemplate" x:DataType="coreVm:CommandParameterRunViewModel">
+                <TextBox
+                    MinHeight="32"
+                    Padding="4,2"
+                    VerticalAlignment="Center"
+                    VerticalContentAlignment="Stretch"
+                    BorderBrush="{ThemeResource AccentTextFillColorPrimaryBrush}"
+                    BorderThickness="1"
+                    Foreground="{ThemeResource AccentTextFillColorPrimaryBrush}"
+                    PlaceholderText="{x:Bind PlaceholderText, Mode=OneWay}"
+                    Style="{StaticResource SearchTextBoxStyle}"
+                    Text="{x:Bind SearchBoxText, Mode=TwoWay}" />
+            </DataTemplate>
             <cpcontrols:ParameterRunTemplateSelector
                 x:Key="ParameterRunTemplateSelector"
                 ButtonParamTemplate="{StaticResource ButtonParamTemplate}"

src/modules/cmdpal/Microsoft.CmdPal.UI/MainWindow.xaml.cs

@@ -46,6 +46,7 @@ public sealed partial class MainWindow : WindowEx,
     IRecipient<ShowWindowMessage>,
     IRecipient<HideWindowMessage>,
     IRecipient<QuitMessage>,
+    IRecipient<GetHwndMessage>,
     IDisposable
 {
     [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Stylistically, window messages are WM_")]
@@ -87,6 +88,7 @@ public sealed partial class MainWindow : WindowEx,
         WeakReferenceMessenger.Default.Register<QuitMessage>(this);
         WeakReferenceMessenger.Default.Register<ShowWindowMessage>(this);
         WeakReferenceMessenger.Default.Register<HideWindowMessage>(this);
+        WeakReferenceMessenger.Default.Register<GetHwndMessage>(this);
 
         // Hide our titlebar.
         // We need to both ExtendsContentIntoTitleBar, then set the height to Collapsed
@@ -747,4 +749,9 @@ public sealed partial class MainWindow : WindowEx,
         _localKeyboardListener.Dispose();
         DisposeAcrylic();
     }
+
+    public void Receive(GetHwndMessage message)
+    {
+        message.Hwnd = this.GetWindowHandle();
+    }
 }

src/modules/cmdpal/ext/SamplePagesExtension/Pages/ParameterSamples.cs

@@ -48,6 +48,38 @@ public sealed partial class SimpleParameterTest : ParametersPage
     public override IListItem Command => new ListItem(_command);
 }
 
+public sealed partial class ButtonParameterTest : ParametersPage
+{
+    private readonly CommandParameterRun _stringParameter;
+    private readonly InvokableCommand _command;
+
+    public ButtonParameterTest()
+    {
+        Name = "Open";
+        _stringParameter = new FilePickerParameterRun();
+
+        _command = new AnonymousCommand(() =>
+        {
+            var input = _stringParameter.Value?.ToString();
+            var toast = new ToastStatusMessage(new StatusMessage() { Message = $"You entered: '{input}'" });
+            toast.Show();
+        })
+        {
+            Name = "Submit",
+            Icon = new IconInfo("\uE724"), // Send
+            Result = CommandResult.KeepOpen(),
+        };
+    }
+
+    public override IParameterRun[] Parameters => new IParameterRun[]
+    {
+        new LabelRun("Enter a value:"),
+        _stringParameter,
+    };
+
+    public override IListItem Command => new ListItem(_command);
+}
+
 public sealed partial class CreateNoteParametersPage : ParametersPage
 {
     private readonly SelectFolderPage _selectFolderPage = new();

src/modules/cmdpal/ext/SamplePagesExtension/Parameters.cs

@@ -95,7 +95,7 @@ public partial class StringParameterRun : ParameterValueRun, IStringParameterRun
     }
 }
 
-public partial class CommandParameterRun : ParameterValueRun
+public partial class CommandParameterRun : ParameterValueRun, ICommandParameterRun
 {
     private string? _displayText;
 
@@ -164,35 +164,25 @@ internal sealed partial class FilePickerParameterRun : CommandParameterRun
 {
     public StorageFile? File { get; private set; }
 
+    public override string? DisplayText { get => File != null ? File.DisplayName : "Select a file"; }
+
     public FilePickerParameterRun()
     {
         var command = new FilePickerCommand();
         command.FileSelected += (s, file) =>
         {
             File = file;
-            if (file != null)
-            {
-                Value = file;
-                DisplayText = file.Name;
-
-                // Icon = new IconInfo("File");
-            }
-            else
-            {
-                Value = null;
-                DisplayText = null;
-
-                // Icon = new IconInfo("File");
-            }
+            Value = file != null ? file : (object?)null;
+            OnPropertyChanged(nameof(DisplayText));
         };
         PlaceholderText = "Select a file";
-        Icon = new IconInfo("File");
+        Icon = new IconInfo("\uE710"); // Add
         Command = command;
     }
 
     private sealed partial class FilePickerCommand : InvokableCommand, IRequiresHostHwnd
     {
-        public override IconInfo Icon => new("File");
+        public override IconInfo Icon => new("\uE710"); // Add
 
         public override string Name => "Pick a file";
 

src/modules/cmdpal/ext/SamplePagesExtension/SamplesListPage.cs

@@ -95,6 +95,11 @@ public partial class SamplesListPage : ListPage
             Title = "Sample parameters page",
             Subtitle = "A demo of a command that takes simple parameters",
         },
+        new ListItem(new ButtonParameterTest())
+        {
+            Title = "Button parameters page",
+            Subtitle = "A demo of a command that takes simple parameters",
+        },
 
         // Evil edge cases
         // Anything weird that might break the palette - put that in here.