Error C2280 occurred when I add data binding

[sxlllslgh]

I am trying to implement a simple data binding with INotifyPropertyChanged to refresh GUI when when value changed.
MainWindow.idl:

namespace App {
    [default_interface]
    runtimeclass MainWindow : Microsoft.UI.Xaml.Window, Microsoft.UI.Xaml.Data.INotifyPropertyChanged {
        Int32 MyValue;
        MainWindow();
    }
}

MainWindow.xaml.h:

namespace winrt::App::implementation {
    struct MainWindow : MainWindowT<MainWindow>, Microsoft::UI::Xaml::Data::INotifyPropertyChanged {
        MainWindow();
    public:
        int32_t MyValue();
        void MyValue(int32_t newValue);
        winrt::event_token PropertyChanged(Microsoft::UI::Xaml::Data::PropertyChangedEventHandler const& handler);
        void PropertyChanged(winrt::event_token const& token);
    private:
        int32_t myValue;
        winrt::event<Microsoft::UI::Xaml::Data::PropertyChangedEventHandler> propertyChanged;
    }
}

MainWindow.xaml.cpp:

void MainWindow::MyValue(int32_t newValue) {
    if (myValue != newValue) {
        myValue = newValue;
        propertyChanged(*this, Microsoft::UI::Xaml::Data::PropertyChangedEventArgs{ L"MyValue" });
    }
}
winrt::event_token MainWindow::PropertyChanged(Microsoft::UI::Xaml::Data::PropertyChangedEventHandler const& handler) {
    return propertyChanged.add(handler);
}
void MainWindow::PropertyChanged(winrt::event_token const& token) {
    propertyChanged.remove(token);
}

MainWindow.xaml:

<TextBlock Text="{x:Bind MyValue, Mode=OneWay}" />

But I got errors like:

1>XamlTypeInfo.Impl.g.cpp
1>D:\App\App\Generated Files\winrt\base.h(7761,5): error C2280: "void *winrt::Windows::Foundation::IUnknown::operator new(size_t)": attempting to reference a deleted function (Compiling source file MainWindow.xaml.cpp)
1>D:\App\App\Generated Files\winrt\base.h(2028): message : see declaration of "winrt::Windows::Foundation::IUnknown::operator new" (Compiling source file MainWindow.xaml.cpp)

How to solve it?

[shelllet]

winrt::eventMicrosoft::UI::Xaml::Data::PropertyChangedEventHandler propertyChanged = {nullptr};

[sxlllslgh]

Thanks but it not work.

[marb2000]

@RealTommyKlein can you help here, please? Here you can find a repro:
https://github.com/marb2000/BasicBindingCpp

[RealTommyKlein]

This is an error in the header file, the winrt::BasicBindingCpp::implementation::MainWindow declaration should not include the INotifyPropertyChanged interface as that's handled by C++/WinRT. The winrt::BasicBindingCpp::implementation::MainWindow declaration in MainWindow.xaml.h should instead look like this:
struct MainWindow : MainWindowT<MainWindow>

That correct declaration is also visible in the Generated Files/sources/MainWindow.h file after a build, even if there's a build error (as long as the .idl files themselves are valid).

The app also needs an implementation of the MyValue property getter, or the app will also get a linker error.

[sxlllslgh]

Thanks very much! It works!

[marb2000]

Thanks Tommy! Doing these two things fix the issues. @sxlllslgh I have updated the repro so you can see it working: https://github.com/marb2000/BasicBindingCpp