我发现您需要设置

GraphicDevice.PreferredBackBufferHeight = height;
GraphicDevice.PreferredBackBufferWidth = width;

当您在游戏类的构造函数中执行此操作时，它会起作用，但是当您尝试在构造函数的外部进行此操作时，还需要调用

When you do this in the constructor of the game class it works, but when you try do to this outside the constructor you also need to call

GraphicsDevice.ApplyChanges();

此外，您可以使用全屏显示(调试时无法正常工作)

Furthermore to have fullscreen (which is not really working correctly while debugging) you can use

if (!GraphicsDevice.IsFullScreen)
   GraphicsDevice.ToggleFullScreen();