我想从我的ViewModel做一些线条绘制操作(即我将添加到我的视图中绑定到ItemsControl
的一组线条。)
为此,我需要知道视图中Image
的高度和宽度。我如何得到它们?
在其他一些SO帖子中提到了一些解决方法,但they are for WPF并没有一个在Metro上工作。
答案 0 :(得分:1)
public static class SizeObserver
{
public static readonly DependencyProperty ObserveProperty = DependencyProperty.RegisterAttached(
"Observe",
typeof(bool),
typeof(SizeObserver), new PropertyMetadata(null, OnObserveChanged));
//new FrameworkPropertyMetadata(OnObserveChanged));
public static readonly DependencyProperty ObservedWidthProperty = DependencyProperty.RegisterAttached(
"ObservedWidth",
typeof(double),
typeof(SizeObserver), null);
public static readonly DependencyProperty ObservedHeightProperty = DependencyProperty.RegisterAttached(
"ObservedHeight",
typeof(double),
typeof(SizeObserver), null);
public static bool GetObserve(FrameworkElement frameworkElement)
{
//frameworkElement.AssertNotNull("frameworkElement");
return (bool)frameworkElement.GetValue(ObserveProperty);
}
public static void SetObserve(FrameworkElement frameworkElement, bool observe)
{
//frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(ObserveProperty, observe);
}
public static double GetObservedWidth(FrameworkElement frameworkElement)
{
//frameworkElement.AssertNotNull("frameworkElement");
return (double)frameworkElement.GetValue(ObservedWidthProperty);
}
public static void SetObservedWidth(FrameworkElement frameworkElement, double observedWidth)
{
//frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(ObservedWidthProperty, observedWidth);
}
public static double GetObservedHeight(FrameworkElement frameworkElement)
{
//frameworkElement.AssertNotNull("frameworkElement");
return (double)frameworkElement.GetValue(ObservedHeightProperty);
}
public static void SetObservedHeight(FrameworkElement frameworkElement, double observedHeight)
{
//frameworkElement.AssertNotNull("frameworkElement");
frameworkElement.SetValue(ObservedHeightProperty, observedHeight);
}
private static void OnObserveChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
var frameworkElement = (FrameworkElement)dependencyObject;
if ((bool)e.NewValue)
{
frameworkElement.SizeChanged += OnFrameworkElementSizeChanged;
UpdateObservedSizesForFrameworkElement(frameworkElement);
}
else
{
frameworkElement.SizeChanged -= OnFrameworkElementSizeChanged;
}
}
private static void OnFrameworkElementSizeChanged(object sender, SizeChangedEventArgs e)
{
UpdateObservedSizesForFrameworkElement((FrameworkElement)sender);
}
private static void UpdateObservedSizesForFrameworkElement(FrameworkElement frameworkElement)
{
// WPF 4.0 onwards
frameworkElement.SetValue(ObservedWidthProperty, frameworkElement.ActualWidth);
frameworkElement.SetValue(ObservedHeightProperty, frameworkElement.ActualHeight);
// WPF 3.5 and prior
////SetObservedWidth(frameworkElement, frameworkElement.ActualWidth);
////SetObservedHeight(frameworkElement, frameworkElement.ActualHeight);
}
}