使用Microsoft Desktop App Converter将Win32应用程序转换为UWP时，如何将文件保存到AppData？

Question

I have a game that was originally written in QuickBasic in the 1990's. I converted it into a Win32 app using QB64. I then used Microsoft's Desktop App Converter to package it as a UWP app and submit it to the Microsoft Store (it's been accepted ).

The game seems to work fine, except for saving files. It throws a permission denied error whenever you try to save a file. From what I've been able to find thus far it seems that UWP apps can't save in the install directory and that is likely what my app is trying to do.

There are a number of code samples available online for taking a Win32 app written in C#, C, C++, etc. and having it use LocalAppData instead. Unfortunately, I'm not seeing anything that will help me with this application.

Is there a way to make saving files work in this instance? I'm hoping that there is perhaps a way to say, "Hey, when I say save a file, I mean save it to the LocalAppData folder for this particular application." This probably needs to be abstract, ideally a declarative part of the appx package that isn't in the QB64 code. Any ideas?

Answer 1

There are two options to fix it (and one way to hack it):

1. If the file saving is done from your code, change it to write to an accessible location instead, such as localappdata or temp.

2. If the file saving is done in code you can't change, then you can use the new Package Support Framework to apply a fixup at runtime that redirects the file operations. This is a new framework coming as part of the 1809 update for Windows 10. At the time of this writing this may not be an option for you just yet. Here is the documentation: https://docs.microsoft.com/en-us/windows/uwp/porting/package-support-framework?context=/windows/msix/render

3. A hacky way to solve it that you could try would be to add a launcher EXE to your package and make that the app's entrypoint. The launcher would then copy your actual EXE to a writeable location (localappdata, etc.) and then launch it from there. All your file writes will then succeed.