Provide the ability to show popups without having to subclass Popup

samples/CommunityToolkit.Maui.Sample/MauiProgram.cs

@@ -197,6 +197,8 @@ static void RegisterViewsAndViewModels(in IServiceCollection services)
 		services.AddTransientPopup<CsharpBindingPopup, CsharpBindingPopupViewModel>();
 		services.AddTransientPopup<UpdatingPopup, UpdatingPopupViewModel>();
 		services.AddTransientPopup<XamlBindingPopup, XamlBindingPopupViewModel>();
+
+		services.AddTransientPopupContent<PopupContentView, PopupContentViewModel>();
 	}
 
 	static void RegisterEssentials(in IServiceCollection services)

samples/CommunityToolkit.Maui.Sample/Pages/Views/Popup/MultiplePopupPage.xaml

@@ -31,6 +31,8 @@
                 <Button Text="C# Binding Popup" Command="{Binding CsharpBindingPopupCommand}" />
 
                 <Button Text="Updating Popup" Command="{Binding UpdatingPopupCommand}" />
+
+                <Button Text="Show Popup content" Command="{Binding ShowPopupContentCommand}" />
             </VerticalStackLayout>
         </ScrollView>
     </ContentPage.Content>

samples/CommunityToolkit.Maui.Sample/ViewModels/Views/Popup/MultiplePopupViewModel.cs

@@ -20,4 +20,12 @@ Task OnUpdatingPopup(CancellationToken token)
 			onPresenting: viewModel => viewModel.PerformUpdates(10),
 			token);
 	}
+
+	[RelayCommand]
+	Task OnShowPopupContent(CancellationToken token)
+	{
+		return popupService.ShowPopupAsync<PopupContentViewModel>(
+			onPresenting: viewModel => viewModel.SetMessage("This is a dynamically set message, shown in a popup without the need to create your own Popup subclass."),
+			token);
+	}
 }

samples/CommunityToolkit.Maui.Sample/ViewModels/Views/Popup/PopupContentViewModel.cs

@@ -0,0 +1,11 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace CommunityToolkit.Maui.Sample.ViewModels.Views;
+
+public sealed partial class PopupContentViewModel : BaseViewModel
+{
+    [ObservableProperty]
+	string message = "";
+
+    internal void SetMessage(string text) => this.Message = text;
+}

samples/CommunityToolkit.Maui.Sample/Views/Popups/PopupContentView.xaml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<Grid
+    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    x:Class="CommunityToolkit.Maui.Sample.Views.Popups.PopupContentView"
+    xmlns:viewModels="clr-namespace:CommunityToolkit.Maui.Sample.ViewModels.Views"
+    x:DataType="viewModels:PopupContentViewModel">
+
+    <Label
+        Text="{Binding Message}"
+        HorizontalTextAlignment="Center"
+        VerticalTextAlignment="Center"
+        Margin="20" />
+
+</Grid>

samples/CommunityToolkit.Maui.Sample/Views/Popups/PopupContentView.xaml.cs

@@ -0,0 +1,13 @@
+using CommunityToolkit.Maui.Sample.ViewModels.Views;
+
+namespace CommunityToolkit.Maui.Sample.Views.Popups;
+
+public partial class PopupContentView : Grid
+{
+	public PopupContentView(PopupContentViewModel popupContentViewModel)
+	{
+		InitializeComponent();
+
+		BindingContext = popupContentViewModel;
+	}
+}

src/CommunityToolkit.Maui/Extensions/ServiceCollectionExtensions.shared.cs

@@ -52,6 +52,25 @@ public static IServiceCollection AddTransientPopup<TPopupView, TPopupViewModel>(
 		return services;
 	}
 
+	/// <summary>
+	/// Adds a <see cref="View"/> of the type specified in <typeparamref name="TPopupContentView"/> and a ViewModel
+	/// of the type specified in <typeparamref name="TPopupViewModel"/> to the specified
+	/// <see cref="IServiceCollection"/> with <see cref="ServiceLifetime.Transient"/> lifetime.
+	/// </summary>
+	/// <typeparam name="TPopupContentView">The type of the Popup to add. Constrained to <see cref="View"/></typeparam>
+	/// <typeparam name="TPopupViewModel">The type of the ViewModel to add. Constrained to 
+	/// <see cref="INotifyPropertyChanged"/></typeparam>
+	/// <param name="services">The <see cref="IServiceCollection"/> to add the service to.</param>
+	/// <returns>A reference to this instance after the operation has completed.</returns>
+	public static IServiceCollection AddTransientPopupContent<TPopupContentView, TPopupViewModel>(this IServiceCollection services)
+		where TPopupContentView : View
+		where TPopupViewModel : INotifyPropertyChanged
+	{
+		PopupService.AddTransientPopupContent<TPopupContentView, TPopupViewModel>(services);
+
+		return services;
+	}
+
 	/// <summary>
 	/// Adds a <see cref="NavigableElement"/> of the type specified in <typeparamref name="TView"/> and a ViewModel
 	/// of the type specified in <typeparamref name="TViewModel"/> to the specified

src/CommunityToolkit.Maui/PopupService.cs

@@ -35,6 +35,16 @@ public PopupService()
 							?? throw new InvalidOperationException("Could not locate IServiceProvider");
 	}
 
+	internal static void AddTransientPopupContent<TPopupContentView, TPopupViewModel>(IServiceCollection services)
+		where TPopupContentView : View
+		where TPopupViewModel : INotifyPropertyChanged
+	{
+		viewModelToViewMappings.Add(typeof(TPopupViewModel), typeof(TPopupContentView));
+
+		services.AddTransient(typeof(TPopupContentView));
+		services.AddTransient(typeof(TPopupViewModel));
+	}
+
 	internal static void AddTransientPopup<TPopupView, TPopupViewModel>(IServiceCollection services)
 		where TPopupView : IPopup
 		where TPopupViewModel : INotifyPropertyChanged
@@ -126,24 +136,52 @@ public void ShowPopup<TViewModel>(Action<TViewModel> onPresenting) where TViewMo
 	/// <exception cref="InvalidOperationException"></exception>
 	static void ValidateBindingContext<TViewModel>(Popup popup, out TViewModel bindingContext)
 	{
-		if (popup.BindingContext is not TViewModel viewModel)
+		if (popup.BindingContext is TViewModel viewModel)
+		{
+			bindingContext = viewModel;
+			return;			
+		}
+		else if (popup.Content?.BindingContext is TViewModel contentViewModel)
 		{
-			throw new InvalidOperationException($"Unexpected type has been assigned to the BindingContext of {popup.GetType().FullName}. Expected type {typeof(TViewModel).FullName} but was {popup.BindingContext?.GetType().FullName ?? "null"}");
+			bindingContext = contentViewModel;
+			return;
 		}
 
-		bindingContext = viewModel;
+		throw new InvalidOperationException($"Unexpected type has been assigned to the BindingContext of {popup.GetType().FullName}. Expected type {typeof(TViewModel).FullName} but was {popup.BindingContext?.GetType().FullName ?? "null"}");
 	}
 
 	Popup GetPopup(Type viewModelType)
 	{
-		var popup = serviceProvider.GetService(viewModelToViewMappings[viewModelType]) as Popup;
+		var view = serviceProvider.GetService(viewModelToViewMappings[viewModelType]);
 
-		if (popup is null)
+		if (view is null)
 		{
 			throw new InvalidOperationException(
 				$"Unable to resolve popup type for {viewModelType} please make sure that you have called {nameof(AddTransientPopup)}");
 		}
 
+		Popup popup;
+
+		if (view is View visualElement)
+		{
+			popup = new Popup
+			{
+				Content = visualElement
+			};
+
+			// Binding the BindingContext property up from the view to the popup so that it is nicely handled on macOS.
+			popup.SetBinding(Popup.BindingContextProperty, new Binding { Source = view, Path = Popup.BindingContextProperty.PropertyName });
+		}
+		else if (view is Popup viewPopup)
+		{
+			popup = viewPopup;
+		}
+		else
+		{
+			throw new InvalidOperationException(
+				$"Invalid type of view being used to present a Popup. Expected either IPopup or View.");
+		}
+
 		return popup;
 	}
 }