大佬教程收集整理的这篇文章主要介绍了Silverlight 行为(Behavior),大佬教程大佬觉得挺不错的,现在分享给大家,也给大家做个参考。
行为的目的在于封装部分UI功能,那样就可以直接应用于元素而不用写任何代码。行为是一组相关操作的组合,它包含了触发器(监听某个事件或改变)和动作(完成适当的操作)的工作。例如,Deep Zoom功能由一些事件处理程序组成,允许通过鼠标按键和鼠标滚轮对Deep Zoom 图像进行平移和缩放。
当用户按下鼠标左键,DragInCanvasBehavior开始拖拽操作,记录下元素左上角与鼠标指针之间的偏移量,并捕获鼠标。
Behavior
命名控件:using System.Windows.Interactivity
程序集:System.Windows.Interactivity.dll
public class DragInCanvasBehavior : Behavior<UIElement> { protected override void OnAttached() { base.onAttached(); //附加事件处理程序 this.AssociatedObject.MouSELEftButtonDown += new MouseButtonEventHandler(AssociatedObject_MouSELEftButtonDown); this.AssociatedObject.MouseMove += new MouseEventHandler(AssociatedObject_MouseMovE); this.AssociatedObject.MouSELEftButtonUp += new MouseButtonEventHandler(AssociatedObject_MouSELEftButtonUp); } protected override void OnDetaching() { base.onDetaching(); //分离事件处理程序 this.AssociatedObject.MouSELEftButtonDown -= new MouseButtonEventHandler(AssociatedObject_MouSELEftButtonDown); this.AssociatedObject.MouseMove -= new MouseEventHandler(AssociatedObject_MouseMovE); this.AssociatedObject.MouSELEftButtonUp -= new MouseButtonEventHandler(AssociatedObject_MouSELEftButtonUp); } //记录当前元素所放置的Canvas private Canvas canvas; //记录当前元素是否正被拖拽 private bool isDragging = false; //当鼠标左键按下的时候,记录单击所在的准确位置 private Point mouSEOffset; private void AssociatedObject_MouSELEftButtonDown(object sender,MouseButtonEventArgs E) { //找到Canvas if (canvas == null) { canvas = (Canvas)VisualTreeHelper.GetParent(this.AssociatedObject); } //拖拽模式开始 isDragging = true; //获取鼠标单击时相对于元素的位置 //因此元素左上角的坐标为(0,0) mouSEOffset = e.GetPosition(AssociatedObject); //捕获鼠标,这样即使用户突然将鼠标指针拽到元素外,仍然可以接收到MouseMove事件 AssociatedObject.CaptureMouse(); } private void AssociatedObject_MouseMove(object sender,MouseEventArgs E) { if (isDragging) { //鼠标指针相对于Canvas的位置 Point point = e.GetPosition(canvas); //重定位元素 Canvas.SetLeft(AssociatedObject,point.X - mouSEOffset.X); Canvas.SetTop(AssociatedObject,point.Y - mouSEOffset.Y); } } private void AssociatedObject_MouSELEftButtonUp(object sender,MouseButtonEventArgs E) { if (isDragging) { AssociatedObject.ReleaseMouseCapture(); isDragging = false; } } }
接下来只要简单的附加到Canvas中的任何元素,就可以使用这个行为。
<UserControl x:Class="SilverlightApplication1.behaviors.behaviorSample" xmlns="http://scheR_203_11845@as.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://scheR_203_11845@as.microsoft.com/winfx/2006/xaml" xmlns:d="http://scheR_203_11845@as.microsoft.com/expression/blend/2008" xmlns:mc="http://scheR_203_11845@as.openxmlformats.org/markup-compatibility/2006" xmlns:custom="clr-namespace:SilverlightApplication1.behaviors" xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <Canvas> <Rectangle Canvas.Left="10" Canvas.Top="10" Width="40" Height="60" Fill="Yellow" /> <Ellipse Canvas.Left="10" Canvas.Top="70" Fill="Blue" Width="80" Height="60"> <i:Interaction.behaviors> <custom:DragInCanvasBehavior /> </i:Interaction.behaviors> </Ellipse> <Ellipse Canvas.Left="80" Canvas.Top="70" Fill="OrangeRed" Width="40" Height="70"> <i:Interaction.behaviors> <custom:DragInCanvasBehavior /> </i:Interaction.behaviors> </Ellipse> </Canvas> </UserControl>
备注: 在后台添加的方法: Interaction.GetBehaviors(textBlock).Add(new ExpandingMouSEOver());
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