问题
I just created a new blank XAML/C# Windows Store app in Visual Studio. I tried to create a file in the Documents folder with this code:
// DEBUG ONLY:
StorageFile file = await KnownFolders.DocumentsLibrary.CreateFileAsync("Hey lol.txt");
But it throws this exception (which I expected):
WinRT information: Access to the specified location (DocumentsLibrary) requires a capability to be declared in the manifest.
Which is fine. I expected it. So I go to Package.appxmanifest and go to Capabilities tab, and to my surprise, there is no "DocumentsLibrary" capability listed.
How do I enable it if it's not even there?
回答1:
Looks like your answer is here. The author shows it available in VS2012, but gone from the list in VS2013, citing MS policy against accessing that particular folder.
[Although] this capability is gone just from the UI, you still can open appxmanifest source and manually add the capability. The result will probably be the same as before – failure of certification for individual developers, so you better stay away from this trick. Microsoft strongly recommend against using Documents Library capability, suggesting Folder and File Pickers instead.
回答2:
As per Grant's answer, a way around this is to add the Capability manually.
Right-click the Package.appxmanifest file in Solution Explorer, and select "View code", then either find the Capabilities element, or add it yourself:
...
<Capabilities>
<Capability Name="internetClient" />
<Capability Name="removableStorage" />
<Capability Name="documentsLibrary" />
</Capabilities>
</Package>
回答3:
Here's what you'll get from the Windows Store when you try to publish it
回答4:
As this is UAP the syntax needs to state this, should be as followed
<Capabilities>
<Capability Name="internetClient" />
<uap:Capability Name="documentsLibrary" />
</Capabilities>
You need to add 'uap:' in front of Capability
来源：https://stackoverflow.com/questions/21225959/how-to-enable-documentslibrary-capability-in-a-windows-store-winrt-app