这篇文章介绍了通过WPF的控件模板以及Thumb来实现图形设计器的移动Drag、改变大小resize和旋转rotate这三个几本功能，示例代码界面如下：
控件模板由ControlTemplate类来表示，它派生自FrameworkTemplate抽象类，它的重要部分是它的VisualTree内容属性，它包含了定义想要的外观的可视树。通过以下方式可以定义一个控件模板类：
<Canvas>
<Canvas.Resources>
<ControlTemplate x:Key="DesignerItemTemplate" TargetType="ContentControl">
<ContentPresenter Content="{TemplateBinding ContentControl.Content}"/>
</ControlTemplate>
</Canvas.Resources>
<ContentControl Name="DesignerItem"
Width="100"
Height="100"
Canvas.Top="100"
Canvas.Left="100"
Template="{StaticResource DesignerItemTemplate}">
<Ellipse Fill="Blue"/>
</ContentControl>
</Canvas>
限制目标类型
ControlTemplate和Style一样，也有一个TargetType属性来限制模板可以被应用到的类型上，如果没有一个显示的TargetType，则目标类型将被隐式的设置为Control。由于没有默认的控件模板，所以它与Style是不同的，当使用TargetType时不允许移除模板的x:Key。
模板绑定TemplateBinding
在控件模板中，从目标元素插入属性值的关键是数据绑定，我们可以通过一个简单、轻量级的模板绑定TemplateBinding来处理。TemplateBinding的数据源总是目标元素，而Path则是目标元素的任何一个依赖属性。使用方式如上例的{TemplateBinding ContentControl.Content}，如果我们设置了TargetType，可以更简单的使用为{TemplateBinding Content}
TemplateBinding仅仅是一个便捷的设置模板绑定的机制，对于有些可冻结的属性（如Brush的Color属性）时绑定会失败，这时候我们可以使用常规的Binding来达到同样效果，通过使用一个RelativeSource，其值为{Relative Source TemplatedParent}以及一个Path。
ContentPresenter
在控件模板中应该使用轻量级的内容显示元素ContentPresenter，而不是ContentControl。ContentPresenter显示的内容和ContentControl是一样的，但是ContentControl是一个带有控件模板的成熟控件，其内部包含了ContentPresenter。
如果我们在使用ContentPresenter时忘记了将它的Content设置为{TemplateBinding Content}时，它将隐式的假设{TemplateBinding Content}就是我们需要的内容
与触发器交互
在模板内部可以使用触发器，但是在进行绑定时需要注意只能使用Binding，因为触发器位于控件可视树模板外部
在WPF中有一个Thumb的控件，在MSDN文档中是这么写的: " ...represents a control that lets the user drag and resize controls." 从字面上来看这个是一个用来处理拖放和设置大小的控件，正好应该在图形设计器中来处理移动和改变大小等动作。在以下介绍的Move、Resize和Rotate这三个功能都是使用Thumb来做的。
MoveThumb 是从Thumb继承下来，我们实现了DragDelta事件来处理移动操作，
代码
public class MoveThumb : Thumb
{
public MoveThumb()
DragDelta += new DragDeltaEventHandler(this.MoveThumb_DragDelta);
}
private void MoveThumb_DragDelta(object sender, DragDeltaEventArgs e)
ContentControl designerItem = DataContext as ContentControl;
if (designerItem != null)
Point dragDelta = new Point(e.HorizontalChange, e.VerticalChange);
RotateTransform rotateTransform = designerItem.RenderTransform as RotateTransform;
if (rotateTransform != null)
dragDelta = rotateTransform.Transform(dragDelta);
Canvas.SetLeft(designerItem, Canvas.GetLeft(designerItem) + dragDelta.X);
Canvas.SetTop(designerItem, Canvas.GetTop(designerItem) + dragDelta.Y);
实现代码中假定DataContext为我们需要操作的图形控件，这个可以在控件模板中看到：
<ControlTemplate x:Key="DesignerItemControlTemplate" TargetType="ContentControl">
<Grid>
<s:DragThumb DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}" Cursor="SizeAll"/>
</Grid>
RelativeSource
PreviousData 列表的前一个数据项
TemplatedParent 应用模板的元素
Self 元素自身
FindAncestor 通过父元素链去找
命中测试 IsHitTestVisible
如果我们现在拖动一个圆形，那么界面如下：
我们现在拖动时会发现，只能在灰色部分才允许拖动，在圆形区域由于捕获的不是MoveThumb而不能拖动。这时候我们只需要简单的设置<code>IsHitTest为false即可</code>
<Ellipse Fill="Blue" IsHitTestVisible="False"/>
更改大小仍旧使用的是Thumb，我们建立了一个控件模板：
<ControlTemplate x:Key="ResizeDecoratorTemplate" TargetType="Control">
<Thumb Height="3" Cursor="SizeNS" Margin="0 -4 0 0"
VerticalAlignment="Top" HorizontalAlignment="Stretch"/>
<Thumb Width="3" Cursor="SizeWE" Margin="-4 0 0 0"
VerticalAlignment="Stretch" HorizontalAlignment="Left"/>
<Thumb Width="3" Cursor="SizeWE" Margin="0 0 -4 0"
VerticalAlignment="Stretch" HorizontalAlignment="Right"/>
<Thumb Height="3" Cursor="SizeNS" Margin="0 0 0 -4"
VerticalAlignment="Bottom" HorizontalAlignment="Stretch"/>
<Thumb Width="7" Height="7" Cursor="SizeNWSE" Margin="-6 -6 0 0"
VerticalAlignment="Top" HorizontalAlignment="Left"/>
<Thumb Width="7" Height="7" Cursor="SizeNESW" Margin="0 -6 -6 0"
VerticalAlignment="Top" HorizontalAlignment="Right"/>
<Thumb Width="7" Height="7" Cursor="SizeNESW" Margin="-6 0 0 -6"
VerticalAlignment="Bottom" HorizontalAlignment="Left"/>
<Thumb Width="7" Height="7" Cursor="SizeNWSE" Margin="0 0 -6 -6"
VerticalAlignment="Bottom" HorizontalAlignment="Right"/>
设置了这个样式的Control界面如下图所示：
对于改变大小，我们只要按照MoveThumb一样，从Thumb继承一个ResizeThumb来处理改变大小的动作，对于控件模板，我们只要把上面的Thumb替换成ResizeThumb即可
public class ResizeThumb : Thumb
public ResizeThumb()
DragDelta += new DragDeltaEventHandler(this.ResizeThumb_DragDelta);
private void ResizeThumb_DragDelta(object sender, DragDeltaEventArgs e)
Control item = this.DataContext as Control;
if (item != null)
double deltaVertical, deltaHorizontal;
switch (VerticalAlignment)
case VerticalAlignment.Bottom:
deltaVertical = Math.Min(-e.VerticalChange,
item.ActualHeight - item.MinHeight);
item.Height -= deltaVertical;
break;
case VerticalAlignment.Top:
deltaVertical = Math.Min(e.VerticalChange,
Canvas.SetTop(item, Canvas.GetTop(item) + deltaVertical);
default:
switch (HorizontalAlignment)
case HorizontalAlignment.Left:
deltaHorizontal = Math.Min(e.HorizontalChange,
item.ActualWidth - item.MinWidth);
Canvas.SetLeft(item, Canvas.GetLeft(item) + deltaHorizontal);
item.Width -= deltaHorizontal;
case HorizontalAlignment.Right:
deltaHorizontal = Math.Min(-e.HorizontalChange,
e.Handled = true;
加入到DesignerItemTemplate控件模板
<Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
<s:MoveThumb Template="{StaticResource MoveThumbTemplate}" Cursor="SizeAll"/>
<Control Template="{StaticResource ResizeDecoratorTemplate}"/>
我们实现旋转功能，仍旧是通过从Thumb继承下来一个RotateThumb，具体实现代码如下：
public class RotateThumb : Thumb
private double initialAngle;
private RotateTransform rotateTransform;
private Vector startVector;
private Point centerPoint;
private ContentControl designerItem;
private Canvas canvas;
public RotateThumb()
DragDelta += new DragDeltaEventHandler(this.RotateThumb_DragDelta);
DragStarted += new DragStartedEventHandler(this.RotateThumb_DragStarted);
private void RotateThumb_DragStarted(object sender, DragStartedEventArgs e)
this.designerItem = DataContext as ContentControl;
if (this.designerItem != null)
this.canvas = VisualTreeHelper.GetParent(this.designerItem) as Canvas;
if (this.canvas != null)
this.centerPoint = this.designerItem.TranslatePoint(
new Point(this.designerItem.Width * this.designerItem.RenderTransformOrigin.X,
this.designerItem.Height * this.designerItem.RenderTransformOrigin.Y),
this.canvas);
Point startPoint = Mouse.GetPosition(this.canvas);
this.startVector = Point.Subtract(startPoint, this.centerPoint);
this.rotateTransform = this.designerItem.RenderTransform as RotateTransform;
if (this.rotateTransform == null)
this.designerItem.RenderTransform = new RotateTransform(0);
this.initialAngle = 0;
else
this.initialAngle = this.rotateTransform.Angle;
private void RotateThumb_DragDelta(object sender, DragDeltaEventArgs e)
if (this.designerItem != null && this.canvas != null)
Point currentPoint = Mouse.GetPosition(this.canvas);
Vector deltaVector = Point.Subtract(currentPoint, this.centerPoint);
double angle = Vector.AngleBetween(this.startVector, deltaVector);
RotateTransform rotateTransform = this.designerItem.RenderTransform as RotateTransform;
rotateTransform.Angle = this.initialAngle + Math.Round(angle, 0);
this.designerItem.InvalidateMeasure();
样式如下：
<!-- RotateThumb Style -->
<Style TargetType="{x:Type s:RotateThumb}">
<Setter Property="RenderTransformOrigin" Value="0.5,0.5"/>
<Setter Property="Cursor" Value="Hand"/>
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type s:RotateThumb}">
<Grid Width="30" Height="30">
<Path Fill="#AAD0D0DD"
Stretch="Fill"
Data="M 50,100 A 50,50 0 1 1 100,50 H 50 V 100"/>
</Setter.Value>
</Setter>
</Style>
<!-- RotateDecorator Template -->
<ControlTemplate x:Key="RotateDecoratorTemplate" TargetType="{x:Type Control}">
<s:RotateThumb Margin="-18,-18,0,0" VerticalAlignment="Top" HorizontalAlignment="Left"/>
<s:RotateThumb Margin="0,-18,-18,0" VerticalAlignment="Top" HorizontalAlignment="Right">
<s:RotateThumb.RenderTransform>
<RotateTransform Angle="90" />
</s:RotateThumb.RenderTransform>
</s:RotateThumb>
<s:RotateThumb Margin="0,0,-18,-18" VerticalAlignment="Bottom" HorizontalAlignment="Right">
<RotateTransform Angle="180" />
<s:RotateThumb Margin="-18,0,0,-18" VerticalAlignment="Bottom" HorizontalAlignment="Left">
<RotateTransform Angle="270" />
<Style x:Key="DesignerItemStyle" TargetType="ContentControl">
<Setter Property="MinHeight" Value="50"/>
<Setter Property="MinWidth" Value="50"/>
<Setter Property="Template">
<ControlTemplate TargetType="ContentControl">
<Control x:Name="RotateDecorator"
Template="{StaticResource RotateDecoratorTemplate}"
Visibility="Collapsed"/>
<s:MoveThumb Template="{StaticResource MoveThumbTemplate}"
Cursor="SizeAll"/>
<Control x:Name="ResizeDecorator"
Template="{StaticResource ResizeDecoratorTemplate}"
<ControlTemplate.Triggers>
<Trigger Property="Selector.IsSelected" Value="True">
<Setter TargetName="ResizeDecorator"
Property="Visibility" Value="Visible"/>
<Setter TargetName="RotateDecorator"
</Trigger>
</ControlTemplate.Triggers>
WPF支持Adorner来修饰WPF控件，在改变大小等情况下我们可以根据需要来显示，有些建模工具支持选中控件后显示快捷工具条，这个就可以通过使用Adorner来实现。
本篇通过建立一个装饰类DesignerItemDecorator控件，加入DesignerItemTemplate中，由DesignerItemDecorator控件来控制是否显示以及如何显示装饰部分。
控件模板
<s:DesignerItemDecorator x:Name="decorator" ShowDecorator="true"/>
<Setter TargetName="decorator" Property="ShowDecorator" Value="true"/>
实现 class DesignerItemDecorator : Control
public class DesignerItemDecorator : Control
private Adorner adorner;
public bool ShowDecorator
get { return (bool)GetValue(ShowDecoratorProperty); }
set { SetValue(ShowDecoratorProperty, value); }
public static readonly DependencyProperty ShowDecoratorProperty =
DependencyProperty.Register
("ShowDecorator", typeof(bool), typeof(DesignerItemDecorator),
new FrameworkPropertyMetadata
(false, new PropertyChangedCallback(ShowDecoratorProperty_Changed)));
private void HideAdorner()
...
private void ShowAdorner()
private static void ShowDecoratorProperty_Changed
(DependencyObject d, DependencyPropertyChangedEventArgs e)
DesignerItemDecorator decorator = (DesignerItemDecorator)d;
bool showDecorator = (bool)e.NewValue;
if (showDecorator)
decorator.ShowAdorner();
decorator.HideAdorner();
实现 class DesignerItemAdorner : Adorner
public class DesignerItemAdorner : Adorner
private VisualCollection visuals;
private DesignerItemAdornerChrome chrome;
protected override int VisualChildrenCount
get
return this.visuals.Count;
public DesignerItemAdorner(ContentControl designerItem)
: base(designerItem)
this.chrome = new DesignerItemAdornerChrome();
this.chrome.DataContext = designerItem;
this.visuals = new VisualCollection(this);
protected override Size ArrangeOverride(Size arrangeBounds)
this.chrome.Arrange(new Rect(arrangeBounds));
return arrangeBounds;
protected override Visual GetVisualChild(int index)
return this.visuals[index];