How can I get the size of an autosized WPF Window?

I have a Window that is autosized around it's content. For an animation I'd need it's width and height. ActualWidth is 开发者_JAVA百科always the max width of the window, Width and Height properties say NaN.

ActualWidth/ActualHeight will give you the actual sizes of the window - given by the layout system, which is based on the actual rendering of the window. These should be the sizes you are looking for. However, there might be a slight delay in the calculation as it is based on rendering, so if they are wrong I guess they aren't calculated yet - and you got a race condition going on.. You can read more about this in links above, where there are some important notes on when the actual sizes are calculated - and hence - why they can be delayed.

Width/Height are requested sizes, and if not set explicitly they will hold their default values, which is Double.NaN.

You can use the Window's UpdateLayout()-Method to have ActualWidth and ActualHeight validated.

Whenever possible you should use a ScaleTransform instead of changing Height and Width values when animating a size change. Not only can it help with performance, but it also gets around issues like this since instead of setting a specific size value which you may not know, the scale values are specified as percentages.