Workaround for Dispatcher.RunIdleAsync

#7

ShortDev.Uwp.FullTrust/Windows/UI/Core/CoreDispatcherExtensions.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Windows.UI.Core
+{
+    public static class CoreDispatcherExtensions
+    {
+        // https://github.com/Microsoft/Windows-task-snippets/blob/master/tasks/UI-thread-task-await-from-background-thread.md
+
+        public static async Task<T> RunTaskAsync<T>(this CoreDispatcher @this, Func<Task<T>> callback, CoreDispatcherPriority priority = CoreDispatcherPriority.Normal)
+        {
+            TaskCompletionSource<T> taskCompletionSource = new();
+            _ = @this.RunAsync(priority, async () =>
+            {
+                try
+                {
+                    taskCompletionSource.SetResult(await callback());
+                }
+                catch (Exception ex)
+                {
+                    taskCompletionSource.SetException(ex);
+                }
+            });
+            return await taskCompletionSource.Task;
+        }
+
+        public static async Task RunTaskAsync(this CoreDispatcher @this, Func<Task> callback, CoreDispatcherPriority priority = CoreDispatcherPriority.Normal)
+            => await RunTaskAsync(
+                    @this,
+                    async () =>
+                    {
+                        await callback();
+                        return true;
+                    },
+                    priority
+                );
+
+        public static async Task RunTaskAsync(this CoreDispatcher @this, Action callback, CoreDispatcherPriority priority = CoreDispatcherPriority.Normal)
+            => await RunTaskAsync(
+                    @this,
+                    () =>
+                    {
+                        callback();
+                        return Task.FromResult(true);
+                    },
+                    priority
+                );
+    }
+}