directui | 国内叫 directui 的一个 Bjarke Viksoe 写的 Windowless UI 库 , Fixed

I am using Visual Studio 2019 16.4.3, Microsoft.Windows.CppWinRT 2.0.200117.5, Windows 10 1809 Pro and targeting 10.0.17763.0.

I am trying to port a C++/CX app to C++ WinRT. I am using data binding of the ItemsSource, SelectedIndexand SelectedItem properties of a combo box but I am running into issues.

For the ItemsSource I am binding to a IObservableVector. The property is implemented using IObservableVector and initialized with single_threaded_observable_vector(std::vector({L"One", L"Two", L"Three"}))

When starting the application I am getting the following exception:

Exception thrown at 0x766B19B2 in BlankCppWinRT.exe: Microsoft C++ exception: winrt::hresult_no_interface at memory location 0x03AED210. occurred

Is this supposed to work? How do I data bind a ItemsSource to a collection of strings? This works in C# and C++/CX. What is the equivalent in C++ WinRT?

When I remove the two way binding to SelectedIndex the application starts and shows the three strings in the combo box, with an empty selected item. But when I try to set the selected index in code by myComboBox().SelectedIndex(0); (in the constructor) I am getting the same exception. Whereas the same line works in the Loaded handler of the page.

Details below.

Any ideas?

Call stack of exception: