Add InstancedBindingFactory

src/AtomUI.Base/Data/InstancedBindingFactory.cs

@@ -0,0 +1,59 @@
+using System.Reactive.Linq;
+using Avalonia.Data;
+
+namespace AtomUI.Data;
+
+internal static class InstancedBindingFactory
+{
+    public static InstancedBinding CreateInstancedBinding(object source,
+                                                          BindingMode mode,
+                                                          BindingPriority priority = BindingPriority.LocalValue)
+    {
+        _ = source ?? throw new ArgumentNullException(nameof(source));
+        if (mode == BindingMode.OneTime)
+        {
+            if (source is IObservable<object?> observable)
+            {
+                return InstancedBinding.OneTime(observable, priority);
+            }
+            return InstancedBinding.OneTime(Observable.Return(source), priority);
+        } else if (mode == BindingMode.OneWay)
+        {
+            if (source is IObservable<object?> observable)
+            {
+                return InstancedBinding.OneWay(observable, priority);
+            }
+            else
+            {
+                throw new ArgumentException("source type must be IObservable<object?>.");
+            }
+        }
+        else if (mode == BindingMode.OneWayToSource)
+        {
+            if (source is IObserver<object?> observer)
+            {
+                return InstancedBinding.OneWayToSource(observer, priority);
+            } 
+            else
+            {
+                throw new ArgumentException("source type must be IObserver<object?>.");
+            }
+        }
+        else if (mode == BindingMode.TwoWay)
+        {
+            if (source is IObserver<object?> observer)
+            {
+                return InstancedBinding.OneWayToSource(observer, priority);
+            } 
+            else
+            {
+                throw new ArgumentException("source type must be IObserver<object?>.");
+            }
+        }
+        else
+        {
+            throw new ArgumentException("mode must be OneTime, OneWay or OneWayToSource.");
+        }
+    }
+    
+}