在XNA中等待KeyPress

Question

I'm trying to learn XNA game programming, now i would like to wait while a Key is Pressed I have Test it with:

while (IsKeyPressed = Keyboard.GetState().IsKeyDown(key));

But IsKeyPressed is also true when the key was released

Answer 1

That code is effectively a spin lock. Don't use spin-locks .

The bug you are seeing is likely because you are using a spin-lock, its not getting a chance to update properly.

Instead, you should read the key being pressed, and set state in whatever class is relevant to stop processing (likely a simple if check in the Update function). Then, when you detect the release, you change the state so the if check will pass.

Something like:

 //Main Update
 if (Keyboard.GetState().IsKeyDown(key))
     myObject.Wait();
 else
     myObject.Continue();

 //Other object
 public void Wait()
 {
    waiting = true;
 }

 public void Continue()
 {
     waiting = false;
 }

 public void Update()
 {
      if (!waiting)
      {
         //Update state
       }
 }

You could always check previous state to avoid calling Wait and Continue repeatedly, but thats going to be something of a micro-optimization with the code provided.