ActualHeight 和 ActualWidth 直到控件被测量和排列后才设置.通常 InitializeComponent() 中没有什么会导致度量，所以当它返回时这些仍然为零.

ActualHeight and ActualWidth are not set until the control is measured and arranged. Usually there is nothing in InitializeComponent() that causes a measure, so when it returns these will still be zero.

您可以通过在窗口的 InitializeComponent() 之后手动调用窗口的 Measure() 和 Arrange() 方法来强制提前计算这些方法代码>返回.

You can force these to be computed earlier by simply calling the window's Measure() and Arrange() methods manually after the window's InitializeComponent() returns.

如果您要根据内容调整大小:

If you are sizing to content:

window.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
window.Arrange(new Rect(0, 0, window.DesiredSize.Width, window.DesiredSize.Height));

如果您使用明确的窗口大小:

If you are using an explicit window size:

window.Measure(new Size(Width, Height));
window.Arrange(new Rect(0, 0, window.DesiredSize.Width, window.DesiredSize.Height));