可拖拽端点的Line

使用wpf提供的Thumb控件做拖拽线的效果：

<UserControl x:Class="DragLine.UserControl1"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:DragLine"
             mc:Ignorable="d" 
             d:DesignHeight="450" d:DesignWidth="800">
    <Canvas>
        <Canvas.Resources>
        <ControlTemplate TargetType="Thumb" x:Key="markerTemplate">
            <Ellipse Fill="{TemplateBinding Background}" 
                             HorizontalAlignment="Stretch" 
                             VerticalAlignment="Stretch"/>
        </ControlTemplate>

        <Style TargetType="Thumb" x:Key="markerStyle">
            <Setter Property="Width" Value="10"/>
            <Setter Property="Height" Value="10" />
            <Setter Property="RenderTransform">
                <Setter.Value>
                    <TranslateTransform X="-5" Y="-5" />
                </Setter.Value>
            </Setter>
            <Setter Property="Cursor" Value="Hand"/>
            <Setter Property="Template" Value="{StaticResource markerTemplate}" />
            <EventSetter Event="DragDelta" Handler="Thumb_DragDelta"/>
            <Style.Triggers>
                <DataTrigger Binding="{Binding Path=.}" Value="{x:Null}">
                    <Setter Property="Visibility" Value="Visible" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
 
    </Canvas.Resources>



    <Thumb x:Name="marker1" 
                   Canvas.Left="{Binding ElementName=line1,Path=X1,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
                   Canvas.Top="{Binding ElementName=line1,Path=Y1,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
                   Background="Red"
                   Style="{StaticResource  markerStyle}" />

    <Thumb x:Name="marker2"                
                   Canvas.Left="{ Binding ElementName=line1, Path=X2,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
                   Canvas.Top="{Binding ElementName=line1,Path=Y2,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
                   Background="Red" 
           Style="{StaticResource  markerStyle}" />
        <Line x:Name="line1" X1="{Binding RelativeSource={RelativeSource   Mode= FindAncestor,  AncestorType={x:Type UserControl}}, Path=StartPoint.X}" Y1="{Binding RelativeSource={RelativeSource   Mode= FindAncestor,  AncestorType={x:Type UserControl}}, Path=StartPoint.Y}" X2="{Binding RelativeSource={RelativeSource   Mode= FindAncestor,  AncestorType={x:Type UserControl}}, Path=EndPoint.X}" Y2="{Binding RelativeSource={RelativeSource   Mode= FindAncestor,  AncestorType={x:Type UserControl}}, Path=EndPoint.Y}" Stroke="Red" StrokeThickness="4"/>
   
    </Canvas>
</UserControl>

/// </summary>
    public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();
        }
        public static readonly DependencyProperty StartPointProperty = DependencyProperty.Register("StartPoint", typeof(Point), typeof(UserControl1));
        public Point StartPoint
        {
            get { return (Point)GetValue(StartPointProperty); }
            set { SetValue(StartPointProperty, value); }
        }

        public static readonly DependencyProperty EndPointProperty = DependencyProperty.Register("EndPoint", typeof(Point), typeof(UserControl1));
        public Point EndPoint
        {
            get { return (Point)GetValue(EndPointProperty); }
            set { SetValue(EndPointProperty, value); }
        }

private void Thumb_DragDelta(object sender, System.Windows.Controls.Primitives.DragDeltaEventArgs e)
        {
            var thumb = (System.Windows.Controls.Primitives.Thumb)sender;
            Canvas.SetLeft(thumb, Canvas.GetLeft(thumb) + e.HorizontalChange);
            Canvas.SetTop(thumb, Canvas.GetTop(thumb) + e.VerticalChange);
        }

    }

调用

 this.gd1.Children.Add(new UserControl1() {StartPoint=new Point (200,100),EndPoint=new Point (100,200)});

效果