构造函数DI - Field永远不会分配给，并且始终具有其默认值

Question

I have the following code:

private IMemoryCache _cache;

public HomeController(IMemoryCache memoryCache) : base() {    
   this._cache = memoryCache;    
}

ASP.Net Core is handling the injection of the IMemoryCache instance via:

public void ConfigureServices(IServiceCollection services) {
   services.AddMemoryCache();
}

It is flagging the _cache field with:

Field HomeController._cache is never assigned to, and will always have its default value null

It's not causing any errors, it is just distracting in the editor.

What is the way to go about convincing Visual Studio 2017 that I am in fact assigning this field a value, via the constructor?

Code (because the error overlaps it):

With the editor showing the error:

At runtime showing the valid instance being injected:

Edit:

For the comments suggesting to use:

private IMemoryCache _cache = null;

... this makes no difference, same exact result.

Answer 1

Restarting Visual Studio 2017 and rebooting did not resolve the issue.

However, I was notified of Visual Studio 2017 update version 15.3.3 when the environment reloaded, which I installed.

After re-starting Visual Studio post-update, this situation is no longer occurring.

I doubt the update actually did anything related to this problem, it's more likely something in my VS configuration was off and the update put things back in place.

Answer 2

Cleaning your solution should solve this. In VS2017 menus: Project -> Clean Solution .

Answer 3

I had the same case on VS2015. In my case Build -> Rebuild Solution resolved the issue.