Add IReadOnlyBindableReactiveProperty<T>

README.md

@@ -913,7 +913,7 @@ public class ValidationViewModel : IDisposable
 
 ![image](https://github.com/Cysharp/R3/assets/46207/f80149e6-1573-46b5-9a77-b78776dd3527)
 
-There is also `IReadOnlyBindableReactiveProperty`, which is preferable when ReadOnly is required in binding. However, unless there are special circumstances, it is recommended to use `BindableReactiveProperty<T>`, which allows mutability.
+There is also `IReadOnlyBindableReactiveProperty<T>`, which is preferable when ReadOnly is required in binding, can create from `IObservable<T>.ToReadOnlyBindableReactiveProperty<T>`.
 
 ### ReactiveCommand
 

sandbox/WpfApp1/MainWindow.xaml.cs

@@ -58,7 +58,7 @@ protected override void OnClosed(EventArgs e)
 public class BasicUsagesViewModel : IDisposable
 {
     public BindableReactiveProperty<string> Input { get; }
-    public IReadOnlyBindableReactiveProperty Output { get; }
+    public IReadOnlyBindableReactiveProperty<string> Output { get; }
 
     public BasicUsagesViewModel()
     {

src/R3/BindableReactiveProperty.cs

@@ -14,18 +14,38 @@ public interface IReadOnlyBindableReactiveProperty : INotifyPropertyChanged, INo
     object? Value { get; }
 }
 
+public interface IReadOnlyBindableReactiveProperty<T> : IReadOnlyBindableReactiveProperty
+{
+    new T Value { get; }
+    IReadOnlyBindableReactiveProperty<T> EnableValidation();
+    IReadOnlyBindableReactiveProperty<T> EnableValidation(Func<T, Exception?> validator);
+    IReadOnlyBindableReactiveProperty<T> EnableValidation<TClass>([CallerMemberName] string? propertyName = null!);
+    IReadOnlyBindableReactiveProperty<T> EnableValidation(Expression<Func<IReadOnlyBindableReactiveProperty<T>?>> selfSelector);
+    Observable<T> AsObservable();
+}
+
 public interface IBindableReactiveProperty : IReadOnlyBindableReactiveProperty
 {
     new object? Value { get; set; }
     void OnNext(object? value);
 }
 
+public interface IBindableReactiveProperty<T> : IBindableReactiveProperty, IReadOnlyBindableReactiveProperty<T>
+{
+    new T Value { get; set; }
+    void OnNext(T value);
+    new IBindableReactiveProperty<T> EnableValidation();
+    new IBindableReactiveProperty<T> EnableValidation(Func<T, Exception?> validator);
+    new IBindableReactiveProperty<T> EnableValidation<TClass>([CallerMemberName] string? propertyName = null!);
+    IBindableReactiveProperty<T> EnableValidation(Expression<Func<IBindableReactiveProperty<T>?>> selfSelector);
+}
+
 // all operators need to call from UI Thread(not thread-safe)
 
 #if NET6_0_OR_GREATER
 [System.Text.Json.Serialization.JsonConverter(typeof(BindableReactivePropertyJsonConverterFactory))]
 #endif
-public class BindableReactiveProperty<T> : ReactiveProperty<T>, IBindableReactiveProperty
+public class BindableReactiveProperty<T> : ReactiveProperty<T>, IBindableReactiveProperty<T>
 {
     IDisposable? subscription;
 
@@ -260,12 +280,49 @@ void IBindableReactiveProperty.OnNext(object? value)
         OnNext((T)value!);
     }
 
-    // IBindableReadOnlyReactiveProperty
+    IBindableReactiveProperty<T> IBindableReactiveProperty<T>.EnableValidation() => EnableValidation();
+
+    IBindableReactiveProperty<T> IBindableReactiveProperty<T>.EnableValidation(Func<T, Exception?> validator) => EnableValidation(validator);
+
+    IBindableReactiveProperty<T> IBindableReactiveProperty<T>.EnableValidation<TClass>(string? propertyName) => EnableValidation<TClass>(propertyName);
+
+    IBindableReactiveProperty<T> IBindableReactiveProperty<T>.EnableValidation(Expression<Func<IBindableReactiveProperty<T>?>> selfSelector)
+    {
+        var memberExpression = (MemberExpression)selfSelector.Body;
+        var propertyInfo = (PropertyInfo)memberExpression.Member;
+        SetValidationContext(propertyInfo);
+
+        enableNotifyError = true;
+        return this;
+    }
+
+    // IReadOnlyBindableReactiveProperty
 
     object? IReadOnlyBindableReactiveProperty.Value
     {
         get => Value;
     }
+
+    IReadOnlyBindableReactiveProperty<T> IReadOnlyBindableReactiveProperty<T>.EnableValidation() => EnableValidation();
+
+    IReadOnlyBindableReactiveProperty<T> IReadOnlyBindableReactiveProperty<T>.EnableValidation(Func<T, Exception?> validator) => EnableValidation(validator);
+
+    IReadOnlyBindableReactiveProperty<T> IReadOnlyBindableReactiveProperty<T>.EnableValidation<TClass>(string? propertyName) => EnableValidation<TClass>(propertyName);
+
+    IReadOnlyBindableReactiveProperty<T> IReadOnlyBindableReactiveProperty<T>.EnableValidation(Expression<Func<IReadOnlyBindableReactiveProperty<T>?>> selfSelector)
+    {
+        var memberExpression = (MemberExpression)selfSelector.Body;
+        var propertyInfo = (PropertyInfo)memberExpression.Member;
+        SetValidationContext(propertyInfo);
+
+        enableNotifyError = true;
+        return this;
+    }
+
+    public Observable<T> AsObservable()
+    {
+        return this;
+    }
 }
 
 internal sealed class PropertyValidationContext(ValidationContext context, ValidationAttribute[] attributes)

src/R3/ReactivePropertyExtensions.cs

@@ -30,12 +30,12 @@ public static BindableReactiveProperty<T> ToBindableReactiveProperty<T>(this Obs
         return new BindableReactiveProperty<T>(source, initialValue, equalityComparer);
     }
 
-    public static IBindableReactiveProperty ToReadOnlyBindableReactiveProperty<T>(this Observable<T> source, T initialValue = default!)
+    public static IReadOnlyBindableReactiveProperty<T> ToReadOnlyBindableReactiveProperty<T>(this Observable<T> source, T initialValue = default!)
     {
         return new BindableReactiveProperty<T>(source, initialValue, EqualityComparer<T>.Default);
     }
 
-    public static IBindableReactiveProperty ToReadOnlyBindableReactiveProperty<T>(this Observable<T> source, IEqualityComparer<T>? equalityComparer, T initialValue = default!)
+    public static IReadOnlyBindableReactiveProperty<T> ToReadOnlyBindableReactiveProperty<T>(this Observable<T> source, IEqualityComparer<T>? equalityComparer, T initialValue = default!)
     {
         return new BindableReactiveProperty<T>(source, initialValue, equalityComparer);
     }
@@ -74,3 +74,4 @@ protected override void OnCompletedCore(Result result)
         }
     }
 }
+