동적으로 행 정의의 높이 가져 오기 MVVM

Question

<Grid.RowDefinitions> 
      <RowDefinition Height="10"/> 
      <RowDefinition Height="*"/> 
      <RowDefinition Height="240"/> 
</Grid.RowDefinitions> 

여기 내 사용자 컨트롤러의 행 정의입니다. 내 Viewmodel에 두 번째 행의 높이를 가져와야합니다. 내가 어떻게 구할 수 있니?

감사합니다.

Answer 1

켄트 Boogaart는 요소의 크기를 관찰하는 속성 첨부 쓴 :

https://stackoverflow.com/a/1083733/4049478

이 아마 관찰자가 문제 (정말 저렴 솔루션에 적용 MVVM

를 사용하여 최적의 솔루션을하지만, 그럼에도 불구하고 용액) :

public class RowDefinitionObserver { 

    public static readonly DependencyProperty ObserveRowProperty = DependencyProperty.RegisterAttached(
     "ObserveRow", 
     typeof(bool), 
     typeof(RowDefinitionObserver), 
     new FrameworkPropertyMetadata(OnObserveChanged)); 

    public static readonly DependencyProperty ObservedRowHeightProperty = DependencyProperty.RegisterAttached(
     "ObservedRowHeight", 
     typeof(double), 
     typeof(RowDefinitionObserver)); 

    public static bool GetObserveRow(FrameworkElement frameworkElement) { 
     return (bool)frameworkElement.GetValue(ObserveRowProperty); 
    } 

    public static void SetObserveRow(FrameworkElement frameworkElement, bool observe) { 
     frameworkElement.SetValue(ObserveRowProperty, observe); 
    } 

    public static double GetObservedRowHeight(FrameworkElement frameworkElement) { 
     return (double)frameworkElement.GetValue(ObservedRowHeightProperty); 
    } 

    public static void SetObservedRowHeight(FrameworkElement frameworkElement, double observedHeight) { 
     frameworkElement.SetValue(ObservedRowHeightProperty, 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) { 
     Grid g = frameworkElement as Grid; 
     if (g != null) { 
      if (g.RowDefinitions.Count > 1) { 
       SetObservedRowHeight(g, g.RowDefinitions[1].ActualHeight); 
      } 
     } 
    } 
} 

사용법 :

<Grid attachedProperties:RowDefinitionObserver.ObserveRow="True" 
     attachedProperties:RowDefinitionObserver.ObservedRowHeight="{Binding RowHeight, Mode=OneWayToSource}"><!--RowHeight is a double Property in your ViewModel--> 
    <Grid.RowDefinitions> 
     <RowDefinition Height="10"/> 
     <RowDefinition Height="*"/> 
     <RowDefinition Height="240"/> 
    </Grid.RowDefinitions> 
    <Grid/> 
    <Grid Grid.Row="1" Background="Red"/> 
    <Grid Grid.Row="2"/> 
</Grid> 

은 적응 당신이 RowDefinition 뒤에 코드에서