silverlight:如何在后端代码中控制Behaviors

今天遇到一个需求，要求能对可拖动的对象提供二种模式：允许拖动、禁止拖动。

之前的拖动为了省事，直接用了：Blend自带的MouseDragElementBehavior，于是就需要在cs代码中控制这个东东了。

折腾了一下，还算简单：

xaml代码

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions" x:Class="slTest.MainPage"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">

    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition MinHeight="22" Height="Auto"/>
        </Grid.RowDefinitions>
        <Canvas Background="Navy" x:Name="c" Cursor="Hand">
            
        	<i:Interaction.Behaviors>
        		<ei:MouseDragElementBehavior/>
        	</i:Interaction.Behaviors>
            
            <TextBlock Foreground="White" FontSize="24">点击拖动Canvas</TextBlock>
            
        </Canvas>
        <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,5">
            <Button  Width="80" Content="允许拖动" x:Name="btnEnable" Click="btnEnable_Click"/>
            <Button  Width="80" Content="禁止拖动" Margin="5,0,0,0" x:Name="btnDisable" Click="btnDisable_Click"/>
        </StackPanel>
    </Grid>
</UserControl>

xaml.cs代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Interactivity;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Expression.Interactivity;
using Microsoft.Expression.Interactivity.Layout;

namespace slTest
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
        }

        private void btnEnable_Click(object sender, RoutedEventArgs e)
        {
            var behaviorsCollection = Interaction.GetBehaviors(c);
            if (behaviorsCollection.Count>0)
            {
                var behavior = behaviorsCollection[0] as MouseDragElementBehavior;
                if (behavior!=null){
                    behavior.Attach(c);
                }
            }

        }

        private void btnDisable_Click(object sender, RoutedEventArgs e)
        {
            var behaviorsCollection = Interaction.GetBehaviors(c);
            if (behaviorsCollection.Count > 0)
            {
                var behavior = behaviorsCollection[0] as MouseDragElementBehavior;
                if (behavior!=null){
                    behavior.Detach();
                }
            }
        }


       
    }
}