我有一个带有Canvas的ItemsPanelTemplate的ListBox。我知道除非给定高度和宽度,否则ScrollViewer不能与Canvas一起使用。我不想给画布一个高度和宽度,因为它不会总是恒定的。有没有任何其他工作或技巧任何人已经为这种情况工作。我知道我不可能是唯一一个有这个问题的人。在此先感谢我的代码到目前为止。
另一个问题是我无法将ScrollViewer放在ItemsPanelTemplate中,因为它只能嵌入一个元素。
这也限制我将画布放在网格中以进行定位。
XAML:
<!--Core Viewer-->
<ScrollViewer x:Name="scrollViewer"
VerticalScrollBarVisibility="Hidden"
HorizontalScrollBarVisibility="Hidden">
<ListBox x:Name="objCoreViewer"
ItemsSource="{Binding ItemsSource}"
Background="LightGray"
SelectionChanged="objCoreViewer_SelectionChanged"
ItemTemplateSelector="{DynamicResource CoreViewerDataTemplateSelector}"
ItemContainerStyleSelector="{DynamicResource ItemContainerStyleSelector}"
PreviewMouseWheel="objCoreViewer_PreviewMouseWheel">
<!-- Core Map Canvas -->
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<Canvas x:Name="objCoreViewerCanvas"
Background="Transparent">
<Canvas.LayoutTransform>
<ScaleTransform ScaleX="{Binding Path=Value, ElementName=ZoomSlider}"
ScaleY="{Binding Path=Value, ElementName=ZoomSlider}" />
</Canvas.LayoutTransform>
</Canvas>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
</ScrollViewer>
答案 0 :(得分:2)
要使画布基于其中的子元素进行增长,您需要在继承自Canavas的自定义类中覆盖Canvas的MeasureOverride事件。这段代码对我很有用:
protected override System.Windows.Size MeasureOverride(System.Windows.Size constraint)
{
Size toReport = new Size();
foreach (UIElement element in this.InternalChildren)
{
//Get the left most and top most point. No using Bottom or Right in case the controls actual bottom and right most points are less then the desired height/width
var left = Canvas.GetLeft(element);
var top = Canvas.GetTop(element);
left = double.IsNaN(left) ? 0 : left;
top = double.IsNaN(top) ? 0 : top;
element.Measure(constraint);
Size desiredSize = element.DesiredSize;
if (!double.IsNaN(desiredSize.Width) && !double.IsNaN(desiredSize.Height))
{
//left += desiredSize.Width;
//top += desiredSize.Height;
toReport.Width = toReport.Width > left +desiredSize.Width ? toReport.Width : left + desiredSize.Width;
toReport.Height = toReport.Height > top+desiredSize.Height ? toReport.Height : top + desiredSize.Height;
}
}
//Make sure scroll includes the margins incase of a border or something
toReport.Width += this.Margin.Right;
toReport.Height += this.Margin.Bottom;
return toReport;
}