Add Drag and Drop GestureRecognizers (#168)

samples/ControlGallery/AppShell.razor

@@ -94,6 +94,7 @@
             <ShadowsPage />
             <GestureEvents />
             <GestureRecognizersPage />
+            <DragAndDropPage />
             <ErrorBoundariesPage />
 
             @if (DeviceInfo.Platform == DevicePlatform.WinUI || DeviceInfo.Platform == DevicePlatform.MacCatalyst)

samples/ControlGallery/Views/Gestures/DragAndDropPage.razor

@@ -0,0 +1,78 @@
+@using Microsoft.Maui.Layouts
+
+<ContentPage Title="Drag And Drop Gestures">
+    <Grid RowDefinitions="*,40">
+        <ScrollView Grid.Row="0" Margin="16">
+            <VerticalStackLayout>
+                <Label Text="Try dragging boxes below" />
+
+                <FlexLayout Wrap="FlexWrap.Wrap">
+                    @foreach (var color in _colors)
+                    {
+                        <BoxView Color="color" HeightRequest="50" WidthRequest="50" Margin="5">
+                            <GestureRecognizers>
+                                <DragGestureRecognizer OnDragStarting="a => DragStarted(a, color)"
+                                                       OnDropCompleted="Dropped" />
+                            </GestureRecognizers>
+                        </BoxView>
+                    }
+                </FlexLayout>
+            </VerticalStackLayout>
+        </ScrollView>
+
+        <Border Grid.Row="1" BackgroundColor="Colors.Red">
+            <GestureRecognizers>
+                <DropGestureRecognizer OnDrop="Delete" />
+            </GestureRecognizers>
+
+            <ChildContent>
+                <Label Text="DELETE"
+                       VerticalOptions="LayoutOptions.Center"
+                       HorizontalOptions="LayoutOptions.Center"
+                       IsVisible="_dragInProgress" />
+            </ChildContent>
+        </Border>
+    </Grid>
+
+</ContentPage>
+
+@code {
+    bool _dragInProgress;
+
+    List<Color> _colors =
+    [
+        Colors.AliceBlue,
+    Colors.Aqua,
+    Colors.Azure,
+    Colors.Beige,
+    Colors.Bisque,
+    Colors.Black,
+    Colors.Blue,
+    Colors.Brown,
+    Colors.BurlyWood,
+    Colors.Crimson,
+    Colors.DarkGray,
+    Colors.CornflowerBlue,
+    Colors.DarkOliveGreen,
+    Colors.Fuchsia,
+    Colors.AliceBlue,
+    Colors.DarkSeaGreen
+    ];
+
+    void DragStarted(DragStartingEventArgs args, Color color)
+    {
+        _dragInProgress = true;
+        args.Data.Properties["Color"] = color;
+    }
+
+    void Dropped()
+    {
+        _dragInProgress = false;
+    }
+
+    void Delete(DropEventArgs args)
+    {
+        var color = (Color)args.Data.Properties["Color"];
+        _colors.Remove(color);
+    }
+}

src/BlazorBindings.Maui/Elements/DragGestureRecognizer.generated.cs

@@ -0,0 +1,78 @@
+// <auto-generated>
+//     This code was generated by a BlazorBindings.Maui component generator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+
+using BlazorBindings.Core;
+using MC = Microsoft.Maui.Controls;
+using Microsoft.AspNetCore.Components;
+using System.Threading.Tasks;
+
+#pragma warning disable MBB001
+
+namespace BlazorBindings.Maui.Elements
+{
+    /// <summary>
+    /// Provides drag gesture recognition and defines the associated events for dragging and dropping.
+    /// </summary>
+    public partial class DragGestureRecognizer : GestureRecognizer
+    {
+        static DragGestureRecognizer()
+        {
+            RegisterAdditionalHandlers();
+        }
+
+        /// <summary>
+        /// Gets or sets the value which indicates whether the element the gesture recognizer is attached to can be a drag source.
+        /// </summary>
+        [Parameter] public bool? CanDrag { get; set; }
+        [Parameter] public EventCallback<MC.DropCompletedEventArgs> OnDropCompleted { get; set; }
+        [Parameter] public EventCallback<MC.DragStartingEventArgs> OnDragStarting { get; set; }
+
+        public new MC.DragGestureRecognizer NativeControl => (MC.DragGestureRecognizer)((BindableObject)this).NativeControl;
+
+        protected override MC.DragGestureRecognizer CreateNativeElement() => new();
+
+        protected override void HandleParameter(string name, object value)
+        {
+            switch (name)
+            {
+                case nameof(CanDrag):
+                    if (!Equals(CanDrag, value))
+                    {
+                        CanDrag = (bool?)value;
+                        NativeControl.CanDrag = CanDrag ?? (bool)MC.DragGestureRecognizer.CanDragProperty.DefaultValue;
+                    }
+                    break;
+                case nameof(OnDropCompleted):
+                    if (!Equals(OnDropCompleted, value))
+                    {
+                        void NativeControlDropCompleted(object sender, MC.DropCompletedEventArgs e) => InvokeEventCallback(OnDropCompleted, e);
+
+                        OnDropCompleted = (EventCallback<MC.DropCompletedEventArgs>)value;
+                        NativeControl.DropCompleted -= NativeControlDropCompleted;
+                        NativeControl.DropCompleted += NativeControlDropCompleted;
+                    }
+                    break;
+                case nameof(OnDragStarting):
+                    if (!Equals(OnDragStarting, value))
+                    {
+                        void NativeControlDragStarting(object sender, MC.DragStartingEventArgs e) => InvokeEventCallback(OnDragStarting, e);
+
+                        OnDragStarting = (EventCallback<MC.DragStartingEventArgs>)value;
+                        NativeControl.DragStarting -= NativeControlDragStarting;
+                        NativeControl.DragStarting += NativeControlDragStarting;
+                    }
+                    break;
+
+                default:
+                    base.HandleParameter(name, value);
+                    break;
+            }
+        }
+
+        static partial void RegisterAdditionalHandlers();
+    }
+}

src/BlazorBindings.Maui/Elements/DropGestureRecognizer.generated.cs

@@ -0,0 +1,83 @@
+// <auto-generated>
+//     This code was generated by a BlazorBindings.Maui component generator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+
+using BlazorBindings.Core;
+using MC = Microsoft.Maui.Controls;
+using Microsoft.AspNetCore.Components;
+using System.Threading.Tasks;
+
+#pragma warning disable MBB001
+
+namespace BlazorBindings.Maui.Elements
+{
+    public partial class DropGestureRecognizer : GestureRecognizer
+    {
+        static DropGestureRecognizer()
+        {
+            RegisterAdditionalHandlers();
+        }
+
+        [Parameter] public bool? AllowDrop { get; set; }
+        [Parameter] public EventCallback<MC.DragEventArgs> OnDragLeave { get; set; }
+        [Parameter] public EventCallback<MC.DragEventArgs> OnDragOver { get; set; }
+        [Parameter] public EventCallback<MC.DropEventArgs> OnDrop { get; set; }
+
+        public new MC.DropGestureRecognizer NativeControl => (MC.DropGestureRecognizer)((BindableObject)this).NativeControl;
+
+        protected override MC.DropGestureRecognizer CreateNativeElement() => new();
+
+        protected override void HandleParameter(string name, object value)
+        {
+            switch (name)
+            {
+                case nameof(AllowDrop):
+                    if (!Equals(AllowDrop, value))
+                    {
+                        AllowDrop = (bool?)value;
+                        NativeControl.AllowDrop = AllowDrop ?? (bool)MC.DropGestureRecognizer.AllowDropProperty.DefaultValue;
+                    }
+                    break;
+                case nameof(OnDragLeave):
+                    if (!Equals(OnDragLeave, value))
+                    {
+                        void NativeControlDragLeave(object sender, MC.DragEventArgs e) => InvokeEventCallback(OnDragLeave, e);
+
+                        OnDragLeave = (EventCallback<MC.DragEventArgs>)value;
+                        NativeControl.DragLeave -= NativeControlDragLeave;
+                        NativeControl.DragLeave += NativeControlDragLeave;
+                    }
+                    break;
+                case nameof(OnDragOver):
+                    if (!Equals(OnDragOver, value))
+                    {
+                        void NativeControlDragOver(object sender, MC.DragEventArgs e) => InvokeEventCallback(OnDragOver, e);
+
+                        OnDragOver = (EventCallback<MC.DragEventArgs>)value;
+                        NativeControl.DragOver -= NativeControlDragOver;
+                        NativeControl.DragOver += NativeControlDragOver;
+                    }
+                    break;
+                case nameof(OnDrop):
+                    if (!Equals(OnDrop, value))
+                    {
+                        void NativeControlDrop(object sender, MC.DropEventArgs e) => InvokeEventCallback(OnDrop, e);
+
+                        OnDrop = (EventCallback<MC.DropEventArgs>)value;
+                        NativeControl.Drop -= NativeControlDrop;
+                        NativeControl.Drop += NativeControlDrop;
+                    }
+                    break;
+
+                default:
+                    base.HandleParameter(name, value);
+                    break;
+            }
+        }
+
+        static partial void RegisterAdditionalHandlers();
+    }
+}

src/BlazorBindings.Maui/Elements/StackLayout.generated.cs

@@ -25,8 +25,11 @@ static StackLayout()
         }
 
         /// <summary>
-        /// Gets or sets the value which indicates the direction which child elements are positioned. Default value is <see cref="F:Microsoft.Maui.Controls.StackOrientation.Vertical" />.
+        /// Gets or sets the value which indicates the direction which child elements are positioned.
         /// </summary>
+        /// <value>
+        /// A <see cref="T:Microsoft.Maui.Controls.StackOrientation" /> which indicates the direction children layouts flow. The default value is Vertical.
+        /// </value>
         [Parameter] public MC.StackOrientation? Orientation { get; set; }
 
         public new MC.StackLayout NativeControl => (MC.StackLayout)((BindableObject)this).NativeControl;

src/BlazorBindings.Maui/Properties/AttributeInfo.cs

@@ -185,6 +185,8 @@
 [assembly: GenerateComponent(typeof(SwipeGestureRecognizer))]
 [assembly: GenerateComponent(typeof(TapGestureRecognizer))]
 [assembly: GenerateComponent(typeof(PointerGestureRecognizer))]
+[assembly: GenerateComponent(typeof(DragGestureRecognizer))]
+[assembly: GenerateComponent(typeof(DropGestureRecognizer))]
 
 
 // Compatibility