如何从MainWindow C＃WPF使用吸气剂

Question

My problem is, that I can't use my getter in my other class because the getter is in the MainWindow.xaml.cs class.

When I use this Code* in my other class ControlKey.cs I get an exception that the Application is hold on. I think it want's to create an other Window but I just want to use the getter in the class ControlKey.cs

MainWindow.xaml.cs Class:

 public bool GetPresentationStarted(){
            return presentationsarted;
 }

---

*

ControlKey.cs Class:

MainWindow mWindow = new MainWindow();

bool presentationStarted;

And later I have an if statement where I do something if presentationStarted is true. ...

presentationStarted = mWindow.GetPresentationStarted();

...

if (presentationStarted == true) {
...
}

I don't know how to do it different. I hope someone can help me

Answer 1

Each instance of MainWindow has its own copy of presentationsarted . If you want the value of presentationsarted from the main window of your application, you can't just create a new instance of MainWindow. That new instance has nothing to do with the other instance that's already showing.

But you can get the actual main window itself.

var mWindow = (MainWindow)App.Current.MainWindow;

var x = mWindow.GetPresentationStarted();

That'll work, but it's not the best way to write a WPF application. You should really learn the MVVM ("Model-View-ViewModel") pattern. Then each window would have its own viewmodel that owns properties like that one, and all the viewmodels can share a reference to some common viewmodel that has state everybody cares about. WPF with the MVVM pattern is immensely powerful. The learning curve is rough, however.

Answer 2

Because you don't require any other parameters from the MainWindow class just try to use: 1. Static property. For example, you can create

public static bool? MainWindow.PresentationStarted {get; private set;} 

and set the value from any event you prefer.

Or

2.Create shared instance like:

public static bool? SharedClass.MainPresentationStarted {get; set;}.

So you have an access to the value:

if (MainWindow.PresentationStarted == true)