Silverlight 2动态创建矩形对象(附完整源代码)-白红宇

使用Silverlight 2的Canvas,写了一个动态创建Rectangle的示例,由于时间的原因所以难免有些不足之处,但程序功能都正常使用.用鼠标可以点击画布任何位置拖出一个矩形对象,松开鼠标即可完成一个矩形的创建!

程序运行效果:

XAML代码:

<UserControl x:Class="Sample.dragrect"

xmlns=" "

xmlns:x=" "

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"/>

<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>

</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