Silverlight 2动态创建矩形对象(附完整源代码)

程序运行效果:

XAML代码:

<UserControl x:Class="Sample.dragrect" 
    xmlns=" http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
    xmlns:x=" http://schemas.microsoft.com/winfx/2006/xaml"  
    Width="780" Height="400"> 
    <StackPanel Background="Green"  
                Orientation="Horizontal"> 
        <Canvas x:Name="LayoutRoot" 
                Background="GreenYellow" 
                Width="650" Height="400" 
                MouseMove="Canvas_MouseMove" 
                MouseLeftButtonDown="Canvas_MouseLeftButtonDown"  
                MouseLeftButtonUp="Canvas_MouseLeftButtonUp"/> 
        <StackPanel Background="Gold" Margin="10"> 
            <TextBlock Text="选择颜色："/> 
            <Button x:Name="btnRed"  
                    Width="100" Height="50"  
                    FontSize="20" Content="Red" Margin="5"  
                    Click="btnRed_Click"/> 
            <Button x:Name="btnBlue"  
                    Width="100" Height="50" 
                    FontSize="20" Content="Blue" Margin="5"  
                    Click="btnBlue_Click"/> 
            <Button x:Name="btnGreen"  
                    Width="100" Height="50" 
                    FontSize="20" Content="Green" Margin="5" 
                    Click="btnGreen_Click"/> 
            <Button x:Name="btnClear"  
                    Width="100" Height="50" 
                    FontSize="20" Content="Clear" Margin="5"  
                    Background="Red" 
                    Click="btnClear_Click"/> 
        </StackPanel> 
    </StackPanel> 
</UserControl>
C#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.Media; 
using System.Windows.Media.Animation; 
using System.Windows.Shapes;

namespace Sample 
{ 
    public partial class dragrect : UserControl 
    { 
        public dragrect() 
        { 
            InitializeComponent(); 
        }

        bool mouseMoveing = false; 
        Point mousePoint; 
        Color rectColor = Colors.Red;

        private void Canvas_MouseMove(object sender, MouseEventArgs e) 
        { 
            //如果鼠标没有拖动矩形则返回 
            if (!mouseMoveing) 
                return; 
            //获取鼠标当前坐标 
            Point curPos = e.GetPosition(null); 
            //取得最小坐标值 
            double posX = mousePoint.X; 
            double posY = mousePoint.Y; 
            //计算矩形的宽和高 
            double rectWidth = Math.Abs(curPos.X - mousePoint.X); 
            double rectHeight = Math.Abs(curPos.Y - mousePoint.Y); 
            //创建一个矩形元素 
            Rectangle rect = new Rectangle(); 
            //声明矩形的宽和高 
            rect.Width = rectWidth; 
            rect.Height = rectHeight; 
            //填充颜色 
            rect.Fill = new SolidColorBrush(rectColor); 
            //声明矩形在Canvas中创建的位置 
            Canvas.SetLeft(rect, posX); 
            Canvas.SetTop(rect, posY); 
            //添加矩形到Canvas中 
            LayoutRoot.Children.Add(rect); 
        }

        private void Canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) 
        { 
            //获取当前的鼠标位置 
            mousePoint = e.GetPosition(null); 
            //开始创建矩形 
            mouseMoveing = true; 
        }

        private void Canvas_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) 
        { 
            //矩形创建完成 
            mouseMoveing = false; 
        }

        private void btnRed_Click(object sender, RoutedEventArgs e) 
        { 
            //声明矩形颜色为Red 
            rectColor = Colors.Red; 
        }

        private void btnBlue_Click(object sender, RoutedEventArgs e) 
        { 
            //声明矩形颜色为Blue 
            rectColor = Colors.Blue; 
        }

        private void btnGreen_Click(object sender, RoutedEventArgs e) 
        { 
            //声明矩形颜色为Green 
            rectColor = Colors.Green; 
        }

        private void btnClear_Click(object sender, RoutedEventArgs e) 
        { 
            //清除所有Canvas内的矩形元素 
            LayoutRoot.Children.Clear(); 
        } 
    } 
}
 

本文转自dotfun 51CTO博客，原文链接:http://blog.51cto.com/dotfun/285833