【发布时间】：2015-09-22 13:48:22
【问题描述】：
这是这个问题的后续：Items added to ItemsControl not using ItemTemplate
我有 2 个类应该处理对象的移动和调整大小（MoveThumb 和 ResizeThumb）。模板被应用于ItemsControl 中的对象，并且正在触发应该转换对象的函数，但我无法让它工作。
ItemsControl 绑定到“DashboardItems”的ObservableCollection，目前只是返回Canvas.SetTop/Left 的X 和Y 的简单对象。我可能会在未来添加它们，但我想先让基础知识发挥作用
在MoveThumb_DragDelta 的比较中，'item' 始终为空。 ResizeThumb 有同样的问题。
发件人是MoveThumb 和sender.DataContext 是ContentPresenter
我的问题是：我应该如何正确设置模板和/或类的数据上下文，以便MoveThumb_DragDelta 可以获取触发它的控件？
编辑：
将 Control item = this.DataContext as Control; 更改为 UIElement item = this.DataContext as UIElement; 使移动正常，但调整大小不起作用，因为 UIElement 不包含 ActualHeight/Width 或 MinHeight/Width。
MoveThumb:
public class MoveThumb : Thumb
{
public MoveThumb()
{
DragDelta += new DragDeltaEventHandler(this.MoveThumb_DragDelta);
}
private void MoveThumb_DragDelta(object sender, DragDeltaEventArgs e)
{
Control item = this.DataContext as Control;
if (item != null)
{
double left = Canvas.GetLeft(item);
double top = Canvas.GetTop(item);
Canvas.SetLeft(item, left + e.HorizontalChange);
Canvas.SetTop(item, top + e.VerticalChange);
}
}
}
MainWindow.xaml:
<Window.Resources>
<ControlTemplate x:Key="MoveThumbTemplate" TargetType="{x:Type local:MoveThumb}">
<Rectangle Fill="Transparent"/>
</ControlTemplate>
<ControlTemplate x:Key="ResizeDecoratorTemplate" TargetType="Control">
<Grid>
<local:ResizeThumb Height="2" Cursor="SizeNS" Margin="0 -4 0 0" VerticalAlignment="Top" HorizontalAlignment="Stretch"/>
<local:ResizeThumb Width="2" Cursor="SizeWE" Margin="-4 0 0 0" VerticalAlignment="Stretch" HorizontalAlignment="Left"/>
<local:ResizeThumb Width="2" Cursor="SizeWE" Margin="0 0 -4 0" VerticalAlignment="Stretch" HorizontalAlignment="Right"/>
<local:ResizeThumb Height="2" Cursor="SizeNS" Margin="0 0 0 -4" VerticalAlignment="Bottom" HorizontalAlignment="Stretch"/>
<local:ResizeThumb Width="7" Height="7" Cursor="SizeNWSE" Margin="-6 -6 0 0" VerticalAlignment="Top" HorizontalAlignment="Left"/>
<local:ResizeThumb Width="7" Height="7" Cursor="SizeNESW" Margin="0 -6 -6 0" VerticalAlignment="Top" HorizontalAlignment="Right"/>
<local:ResizeThumb Width="7" Height="7" Cursor="SizeNESW" Margin="-6 0 0 -6" VerticalAlignment="Bottom" HorizontalAlignment="Left"/>
<local:ResizeThumb Width="7" Height="7" Cursor="SizeNWSE" Margin="0 0 -6 -6" VerticalAlignment="Bottom" HorizontalAlignment="Right"/>
</Grid>
</ControlTemplate>
<DataTemplate DataType="{x:Type local:TableControl}">
<Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
<local:MoveThumb Template="{StaticResource MoveThumbTemplate}" DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}" Cursor="SizeAll"/>
<Control Template="{StaticResource ResizeDecoratorTemplate}"/>
<Button Content="x" VerticalAlignment="Top" HorizontalAlignment="Right" Width="10" Height="10" Click="Button_Click"/>
<Ellipse Fill="Red" IsHitTestVisible="False" Height="100" Width="100"/>
</Grid>
</DataTemplate>
<DataTemplate DataType="{x:Type local:GraphControl}">
<Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
<local:MoveThumb Template="{StaticResource MoveThumbTemplate}" DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}" Cursor="SizeAll"/>
<Control Template="{StaticResource ResizeDecoratorTemplate}"/>
<Button Content="x" VerticalAlignment="Top" HorizontalAlignment="Right" Width="10" Height="10" Click="Button_Click"/>
<Ellipse Fill="Green" IsHitTestVisible="False" Height="100" Width="100"/>
</Grid>
</DataTemplate>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ribbon:Ribbon Margin="0,-22,0,0" Grid.Row="0">
<ribbon:RibbonTab Header="Dashboard">
<ribbon:RibbonGroup Header="Customise">
<ribbon:RibbonMenuButton Label="New" FontSize="20" Height="60" Width="60">
<ribbon:RibbonMenuItem Header="Graph" Click="NewGraph"/>
<ribbon:RibbonMenuItem Header="Table" Click="NewTable"/>
</ribbon:RibbonMenuButton>
</ribbon:RibbonGroup>
</ribbon:RibbonTab>
</ribbon:Ribbon>
<ItemsControl Name="dashboardControls" ItemsSource="{Binding Path=CanvasContents}" Grid.Row="1">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style>
<Setter Property="Canvas.Top" Value="{Binding Path=Y}"/>
<Setter Property="Canvas.Left" Value="{Binding Path=X}"/>
</Style>
</ItemsControl.ItemContainerStyle>
</ItemsControl>
</Grid>
MainWindow.xaml.cs:
public partial class MainWindow : Window
{
public static Dashboard dashboard;
public MainWindow()
{
dashboard = new Dashboard();
InitializeComponent();
this.DataContext = dashboard;
}
private void NewGraph(object sender, RoutedEventArgs e)
{
dashboard.CanvasContents.Add(new GraphControl());
}
private void NewTable(object sender, RoutedEventArgs e)
{
dashboard.CanvasContents.Add(new TableControl());
}
}
Dashboard.cs:
public class Dashboard: INotifyPropertyChanged
{
ObservableCollection<DashboardItem> _canvasContents;
public Dashboard()
{
_canvasContents = new ObservableCollection<DashboardItem>();
}
public ObservableCollection<DashboardItem> CanvasContents
{
get { return _canvasContents; }
}
}
DashboardItem.cs:
public abstract class DashboardItem
{
public int X
{
get { return 100; }
}
public int Y
{
get { return 100; }
}
}
【问题讨论】：
标签： c# wpf xaml datacontext