WPF中拖动控件,实现位置随意摆放[2]

在WPF中,除了可以通过处理鼠标事件来实现控件位置的拖动以外,还可以通过定义一些控件的行为,来实现控件的拖动,具体操作步骤如下:

自定义实现拖动的类库

1. 使用VS2010建立一个C#的类库

2. 增加"System.Windows.Interactivity.dll"库的引用\

    如果使用的是Blend4,则位置为:"C:\Program Files\Microsoft SDKs\Expression\Blend\.NETFramework\v4.0\Libraries"

    如果使用的是Blend3,则位置为:"C:\Program Files\Microsoft SDKs\Expression\Blend 3\Interactivity\Libraries\WPF"

3. 向项目中添加一个新的类文件.并命名为"DrapControlLibrary.cs",该文件的源码如下

using System;using System.Net;using System.Windows;using System.Windows.Controls;using System.Windows.Documents;using System.Windows.Ink;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Animation;using System.Windows.Shapes;using System.Windows.Interactivity;namespace DrapControlLibrary{    public class DragInCanvasBehavior : Behavior<UIElement>    {        private Canvas canvas;        protected override void OnAttached()        {            base.OnAttached();            // Hook up event handlers.                        this.AssociatedObject.MouseLeftButtonDown += AssociatedObject_MouseLeftButtonDown;            this.AssociatedObject.MouseMove += AssociatedObject_MouseMove;            this.AssociatedObject.MouseLeftButtonUp += AssociatedObject_MouseLeftButtonUp;        }        protected override void OnDetaching()        {            base.OnDetaching();            // Detach event handlers.            this.AssociatedObject.MouseLeftButtonDown -= AssociatedObject_MouseLeftButtonDown;            this.AssociatedObject.MouseMove -= AssociatedObject_MouseMove;            this.AssociatedObject.MouseLeftButtonUp -= AssociatedObject_MouseLeftButtonUp;        }        // Keep track of when the element is being dragged.        private bool isDragging = false;        // When the element is clicked, record the exact position        // where the click is made.        private Point mouseOffset;        private void AssociatedObject_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)        {            // Find the canvas.            if (canvas == null) canvas = VisualTreeHelper.GetParent(this.AssociatedObject) as Canvas;            // Dragging mode begins.            isDragging = true;            // Get the position of the click relative to the element            // (so the top-left corner of the element is (0,0).            mouseOffset = e.GetPosition(AssociatedObject);            // Capture the mouse. This way you'll keep receiveing            // the MouseMove event even if the user jerks the mouse            // off the element.            AssociatedObject.CaptureMouse();        }        private void AssociatedObject_MouseMove(object sender, MouseEventArgs e)        {            if (isDragging)            {                // Get the position of the element relative to the Canvas.                Point point = e.GetPosition(canvas);                // Move the element.                AssociatedObject.SetValue(Canvas.TopProperty, point.Y - mouseOffset.Y);                AssociatedObject.SetValue(Canvas.LeftProperty, point.X - mouseOffset.X);            }        }        private void AssociatedObject_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)        {            if (isDragging)            {                AssociatedObject.ReleaseMouseCapture();                isDragging = false;            }        }    }}

4. 编译生成类库文件,类库文件名称为"DrapControlLibrary.dll"

制作测试程序

1. 使用Blend4新建一个WPF程序

2. 修改主XAML文件,修改后的结果如下

<Windowxmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"         xmlns:custom="clr-namespace:DrapControlLibrary;assembly=DrapControlLibrary" xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"x:Class="DrapControlTest.MainWindow"x:Name="Window"Title="DrapControlTest"Width="300" Height="250" ResizeMode="CanMinimize" Background="White">    <Canvas>        <TreeView Canvas.Left="10" Canvas.Top="80" Width="200" Height="50">            <i:Interaction.Behaviors>                <custom:DragInCanvasBehavior/>            </i:Interaction.Behaviors>        </TreeView>        <ListView Canvas.Left="10" Canvas.Top="15" Width="200" Height="50">            <i:Interaction.Behaviors>                <custom:DragInCanvasBehavior/>            </i:Interaction.Behaviors>        </ListView>         <Rectangle Canvas.Left="10" Canvas.Top="10" Fill="Yellow" Width="40" Height="60"/>        <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></Window>

3. 编译文件,能够看到效果了吧?是不是很帅