C# 在ViewBox/Canvas对象中查找子对象
我已经实现了一个拖放,它主要在我的Silverlight 4应用程序中工作。一旦用户将形状放到画布上,我就想使用。我已尝试实现示例代码。下面的代码是更大的应用程序的问题部分 克马尔-C# 在ViewBox/Canvas对象中查找子对象,c#,silverlight,silverlight-4.0,C#,Silverlight,Silverlight 4.0,我已经实现了一个拖放,它主要在我的Silverlight 4应用程序中工作。一旦用户将形状放到画布上,我就想使用。我已尝试实现示例代码。下面的代码是更大的应用程序的问题部分 克马尔- <ScrollViewer Grid.RowSpan="1" Grid.Row="2" Grid.ColumnSpan="2" Grid.Column="2" Name="scrollViewer"> <Viewbox Margin="0" MinWidth="400" MinHeigh
<ScrollViewer Grid.RowSpan="1" Grid.Row="2" Grid.ColumnSpan="2" Grid.Column="2" Name="scrollViewer">
<Viewbox Margin="0" MinWidth="400" MinHeight="500"
HorizontalAlignment="Left" VerticalAlignment="Top" Name="ViewBoxTestBuild">
<Canvas x:Name="Camera1Canvas" telerikDragDrop:RadDragAndDropManager.AllowDrop="True"
Width="1200" Height="768" MouseLeftButtonDown="Camera1Canvas_MouseLeftButtonDown">
<Image x:Name="Camera1Image" Source="timemagadj.jpg" Canvas.ZIndex="-1"
HorizontalAlignment="Left" VerticalAlignment="Top" />
<local:Three_Line_Graphic x:Name="threeLineEditTool"
HorizontalAlignment="Left" Canvas.Left="594" Canvas.Top="621" />
<l:Adorner x:Name="adorn" Canvas.ZIndex="100" />
</Canvas>
</Viewbox>
</ScrollViewer>
我的问题是,当在鼠标左键单击事件中调用VisualTreeHelper.FindElementsInHostCoordinates时,当我单击任何对象时,它不会返回任何元素。我确信这是一个坐标映射问题,但由于这是我的新领域,我不确定如何解决它。您需要将VisualTreeHelper行更改为
GeneralTransform transform = sendingObj.TransformToVisual(Application.Current.RootVisual);
Point pnt = transform.Transform(e.GetPosition(sendingObj));
var elements = VisualTreeHelper.FindElementsInHostCoordinates(pnt,Application.Current.RootVisual);
在您的情况下,可能不需要使用VisualTreeHelper方法 由于您控制画布中的元素,并且知道它们的类型,因此可以尝试以下操作:
private void Camera1Canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var sendingObj = sender as Canvas;
if (sendingObj == null) return;
foreach (UserControl l in sendingObj.Children)
{
var position = e.GetPosition(l);
var lArea = new Rect(0,0,l.ActualWidth,l.ActualHeight);
if (lArea.Contains(position))
{
adorn.AdornedElement = l as FrameworkElement;
adorn.adorned_MouseLeftButtonDown(l, e);
break;
}
}
base.OnMouseLeftButtonDown(e);
}
这比命中测试更有效。但是,这仅在矩形区域可接受时有效
如果需要检测矩形以外的形状,则可以使用以下方法,只要将UserControl实例填充到画布中:
private void Camera1Canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var sendingObj = sender as Canvas;
if (sendingObj == null) return;
var elements = VisualTreeHelper
.FindElementsInHostCoordinates(
e.GetPosition(sendingObj), sendingObj);
foreach (var l in elements)
{
if (l is UserControl)
{
adorn.AdornedElement = l as FrameworkElement;
adorn.adorned_MouseLeftButtonDown(l, e);
break;
}
}
base.OnMouseLeftButtonDown(e);
}
您的建议仍然没有返回任何元素。请编辑以显示其他方式。SL坐标系有点古怪,有几个怪癖。只需修改一下就可以了:“VisualTreeHelper.FindElementsInHostCoordinates(pnt,sendingObj);”我喜欢这个答案,我以后会使用它。谢谢
private void Camera1Canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var sendingObj = sender as Canvas;
if (sendingObj == null) return;
var elements = VisualTreeHelper
.FindElementsInHostCoordinates(
e.GetPosition(sendingObj), sendingObj);
foreach (var l in elements)
{
if (l is UserControl)
{
adorn.AdornedElement = l as FrameworkElement;
adorn.adorned_MouseLeftButtonDown(l, e);
break;
}
}
base.OnMouseLeftButtonDown(e);
}