Merge pull request #12160 from Enscape/feature/untyped-property-observable-converter

Support non-generic `AvaloniaProperty` in `GetObservable(converter)`

src/Avalonia.Base/AvaloniaObjectExtensions.cs

@@ -60,6 +60,8 @@ namespace Avalonia
         }
 
         /// <inheritdoc cref="GetObservable{T}(AvaloniaObject, AvaloniaProperty{T})"/>
+        /// <typeparam name="TSource">The type of the values held by the <paramref name="property"/>.</typeparam>
+        /// <typeparam name="TResult">The type of the value returned by the <paramref name="converter"/>.</typeparam>
         /// <param name="o"/>
         /// <param name="property"/>
         /// <param name="converter">A method which is executed to convert each property value to <typeparamref name="TResult"/>.</param>
@@ -71,6 +73,15 @@ namespace Avalonia
                 converter ?? throw new ArgumentNullException(nameof(converter)));
         }
 
+        /// <inheritdoc cref="GetObservable{TSource,TResult}"/>
+        public static IObservable<TResult> GetObservable<TResult>(this AvaloniaObject o, AvaloniaProperty property, Func<object?, TResult> converter)
+        {
+            return new AvaloniaPropertyObservable<object?, TResult>(
+                o ?? throw new ArgumentNullException(nameof(o)),
+                property ?? throw new ArgumentNullException(nameof(property)),
+                converter ?? throw new ArgumentNullException(nameof(converter)));
+        }
+
         /// <summary>
         /// Gets an observable for an <see cref="AvaloniaProperty"/>.
         /// </summary>
@@ -92,6 +103,15 @@ namespace Avalonia
                 property ?? throw new ArgumentNullException(nameof(property)));
         }
 
+        /// <inheritdoc cref="GetObservable{TSource,TResult}"/>
+        public static IObservable<BindingValue<TResult>> GetBindingObservable<TResult>(this AvaloniaObject o, AvaloniaProperty property, Func<object?, TResult> converter)
+        {
+            return new AvaloniaPropertyBindingObservable<object?, TResult>(
+                o ?? throw new ArgumentNullException(nameof(o)),
+                property ?? throw new ArgumentNullException(nameof(property)),
+                converter?? throw new ArgumentNullException(nameof(converter)));
+        }
+
         /// <summary>
         /// Gets an observable for an <see cref="AvaloniaProperty"/>.
         /// </summary>