Windows.ApplicationModel不存在，为什么？

Question

I met an UWP issue, and asked question as below post: How to detect user idle in UWP?

Thanks for Nico to answer my question! And he provided an example code here: https://stefanwick.com/2018/05/15/global-hotkey-registration-in-uwp/ https://github.com/StefanWickDev/ExtensionGallery/tree/master/GlobalHotkey

Some of the codes which report compile errors are:

using Windows.ApplicationModel;
using Windows.ApplicationModel.AppService;
using Windows.ApplicationModel.Core;
using Windows.Foundation.Collections;
using Windows.Storage;

But I cannot run the above code, I mean the GlobalHotkey project. I got 18 compile errors as below picture shown.

The first error is:

The type or namespace name 'ApplicationModel' does not exist in the namespace 'Windows'

I cannot find Windows.ApplicationModel by this way:

Project -> Right Click -> Add -> Reference -> Assemblies -> Search "System.Drawing"

Like this picture shown:

And I did not change the code at all. I also install the SDK Build 17134, which is required by the original code. Why?

More: To answer Pavel Anikhouski's question, please check below picture. I have the two files, and no items under Universal Windows subtree.

Answer 1

Windows.ApplicationModel does not exist, why?

The problem is you have missed Windows.winmd reference for Desktop App. You could find it with this path C:\\Program Files (x86)\\Windows Kits\\10\\UnionMetadata\\10.0.xxxxxx.0\\Windows.winmd for more please refer this case reply .

If your project has missed Windows Desktop Extension for UWP lib, Please install windows sdk and search it in extension list as you mentioned.