microsoft-ui-xaml | Windows UI Library: the latest Windows 10 native controls and Fluent styles for your applications | Runtime Evironment library

My app builds fine. Attempting to start it in debug mode, however, causes this error. This appeared after I solved an error relating to missing "debug symbols" similar to the one here (enabling the remote symbol servers in the options and then building caused this error to appear instead - this behavior persisted even after turning off the remote symbol servers in the options again).

I am using WinUI3 project on Visual Studio 2022 on Windows 11.

This post seems to suggest the issue was using WPF - but I am not using WPF. I also see a potentially similar issue here, but there appear to be no answers.

I am not sure where to even begin fixing this - it seems to be a Visual Studio issue or a project/solution config issue rather than a code issue. Any ideas?

My solution structure looks like this:

The compiler complains that it finds duplicate types (of every public interface/class) in WCL1.winmd b/c that winmd file already exists in WCL4's bin directory.

One problem is that I know absolutely nothing about C++ and the link offered in the Answer to this question provides a C++ workaround that doesn't help (it's literally like reading a different-but-related language -- i.e. reading German when I only know English).

I also found this which provides another workaround but doesn't tell you where to put it. I added the specified ItemGroupDescription element into every .csproj file as well as the application's PropertySheet.props file to no avail.

I have also done the following:

• Moved the code from WCL2 into WCL3 and removed WCL2 from the solution.
• Had the application reference WCL1, WCL3 and WCL4.

Anyone else got any ideas? It would be greatly appreciated....

UPDATE:

Here's a link to a small solution that reproduces the compile errors. It seems that it comes from the Microsoft.Windows.CppWinRT NuGet package referenced by the C++ Application. That package auto-generates C++ header files from the .winmd files generated by the component projects referenced by the Application.

In a WinUI 3 in Desktop app I have a property to update which is bound to the ui via x:Bind.

I want to use the Dispatcher like I do in WPF to get on the UI thread and avoid the thread error im getting when I update the prop:

System.Runtime.InteropServices.COMException: 'The application called an interface that was marshalled for a different thread. (0x8001010E (RPC_E_WRONG_THREAD))'

Im just not sure how to do it in WinUI 3, when I try

I have created the custom controls. I have did the code changes to fix the issue in the AppWindow by setting the XamlRoot. But what's my problem is XamlRoot is available only in latest version.

So I changed the source target version to the latest version. When I create the UWP app with the same version of custom control, it works fine. But when the UWP project version has a lower target version (which doesn't support XamlRoot), I have got an exception:

Method Not Found

I have checked the conditions to execute the XamlRoot code only when targetversion is higher. But it does not work. I have tried with ApiInformation, but it is also of no use, since this is only to make the UWP app compatible for every device and not depends on the App TargetVersion.

Please refer the below code which I uses to fix the issue in the popUp

In the ctor of the code-behind we have the code below copied from microsoft-ui-xaml-specs

I have this code:

I created a new UWP project with a NavigationView (winui 2.4) in MainPage.xaml.

I proceeded by binding a hierarchical ObservableCollection to populate the NavigationView menu items (1 parent, 4 children)

Launching the application, the hierarchical structure renders as expected, and seem to be working fine.

My next objective would be to collapse every expanded menu item clicking on a button. To do so, the docs suggest using NavigationView.Collapse(NavigationViewItem): my intention would be to iterate through NavigationView.MenuItems and collapse them.

The issue is that it seems NavigationView.MenuItems returns empty and I cannot figure out why. I included a Button that prints NavigationView.MenuItems.Count(), which returns 0.

On the other hand, hard-coding the hierarchical menu items and repeating said procedure seem to work fine.

MainPage.xaml

I have come across a layout / template problem with CommandBar of which symptoms are seen in several pages:

• UWP - CommandBar blank space under Buttons
• https://github.com/microsoft/microsoft-ui-xaml/issues/1024

It seems that the UWP CommandBar elements inside the CommandBar have an actual height of 44px, which is cropped in a control of 40px.

• When IsOpen="False", the AppBarButtons are vertically centered and the bottom 4px of the CommandBar.Content section is not shown
• When IsOpen="Top", the AppBarButtons are shifted up, an ugly gap appears under them and the bottom 4px of the CommandBar.Content section is suddenly shown

Besides the ugly gap, it makes it very difficult to correctly vertically center elements in CommandBar.Content.

About the vertical position of the CommandBar

• When the CommandBar is at the top of the Page, the CommandBar itself does not vertically resize.
• When the CommandBar is at the bottom of the Page, the CommandBar itself grows vertically with 4px.
• In all cases, the other symptoms happen

The red line visualizes the bottom 4px of the CommandBar.Content section. Also, with the Reveal effect to the left of the mouse cursor you can see that the buttons shift up. The whole CommandBar grows vertically

Is there any way to workaround this issue? Microsoft has qualified this more than a year ago as something they might fix in WinUI 3 which is far away.

https://github.com/hansmbakker/CommandBar.BugRepro

I have an issue with the NavigationView control in my UWP app. When I set the IsPaneToggleButtonVisible to false, my PaneHeader collapses too. Offically this bug was solved, am I doing something wrong?