Silverlight画几何图形并拖动

Silverlight 开源项目分析Live Geometry CTP 2（2）项目框架分析

在线地址：http://geometry.osenkov.com

源码地址：http://livegeometry.codeplex.com/

没看懂Live Geometry只好自己摸索了。

<UserControl x:Class="SilverlightUndo.DrawDrag"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="400" Height="300">
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.RowDefinitions>
            <RowDefinition Height="50"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="50"></ColumnDefinition>
            <ColumnDefinition Width="50"></ColumnDefinition>
            <ColumnDefinition Width="*"></ColumnDefinition>
        </Grid.ColumnDefinitions>
        <Button Grid.Row="0" Grid.Column="0" Content="拖动" Name="btnDrag" Click="btnDrag_Click"></Button>
        <Button Grid.Row="0" Grid.Column="1" Content="直线" Name="btnLine" Click="btnLine_Click"></Button>
        <Canvas Name="Board" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="3" Background="Black" MouseLeftButtonDown="Canvas_MouseLeftButtonDown"></Canvas>
    </Grid>
</UserControl>
 

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 SilverlightUndo
{
    public partial class DrawDrag : UserControl
    {
        Ellipse ellipse = new Ellipse();//画点
        int iOper = 1;//默认画直线
        private bool IsStart = true;//是否是起点。
        private double pX1 = 0, pY1 = 0;//起点坐标
        //
        bool trackingMouseMove = false;
        Point mousePosition;
        public DrawDrag()
        {
            InitializeComponent();
        }

        private void btnDrag_Click(object sender, RoutedEventArgs e)
        {
            iOper = 0;
        }

        private void btnLine_Click(object sender, RoutedEventArgs e)
        {
            iOper = 1;
        }
        private void Canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            if (iOper == 0) return;//如果是拖动状态
            Point p = e.GetPosition(sender as FrameworkElement);//取得鼠标点下的位置
            Canvas pnl = sender as Canvas;
            if (IsStart)
            {
                pX1 = p.X;//设置起点坐标
                pY1 = p.Y;
            }
            if (IsStart)//如果是起点，则画起点。
            {
                DrawPoint(pnl, p.X, p.Y);
            }
            else
            {
                DrawOneLine(pnl, pX1, pY1, p.X, p.Y);
            }
            IsStart = !IsStart;
        }
        //画点
        private void DrawPoint(Canvas pnl, double pX1, double pY1)
        {
            
            ellipse.Stroke = new SolidColorBrush(Color.FromArgb(255, 255, 255, 255));//动态设置Stroke属性的方法。
            ellipse.StrokeThickness = 2;
            ellipse.Width = 4;
            ellipse.Height = 4;
            Canvas.SetLeft(ellipse, pX1);//动态设置Ellipse的Canvas.Top与Canvas.Left
            Canvas.SetTop(ellipse, pY1);

            pnl.Children.Add(ellipse);
        }
        //画直线
        private void DrawOneLine(Canvas pnl, double pX1, double pY1, double pX2, double pY2)
        {
            Line line = new Line();
            line.X1 = pX1;
            line.Y1 = pY1;
            line.X2 = pX2;
            line.Y2 = pY2;
            //注册事件
            line.MouseLeftButtonDown += new MouseButtonEventHandler(OnMouseDown);
            line.MouseMove += new MouseEventHandler(OnMouseMove);
            line.MouseLeftButtonUp += new MouseButtonEventHandler(OnMouseUp);

            line.Stroke = new SolidColorBrush(Color.FromArgb(255, 255, 255, 255));
            line.StrokeThickness = 4;

            pnl.Children.Add(line);
            pnl.Children.Remove(ellipse);
        }

        void line_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            throw new NotImplementedException();
        }
        //
        void OnMouseDown(object sender, MouseButtonEventArgs e)
        {
            if (iOper == 1) return;
            FrameworkElement element = sender as FrameworkElement;//当前元件
            mousePosition = e.GetPosition(null);//鼠标位置
            trackingMouseMove = true;
            if (null != element)
            {
                element.CaptureMouse();//设置鼠标捕获
                element.Cursor = Cursors.Hand;
                Line line = (Line)element;//选中
                line.Stroke = new SolidColorBrush(Colors.Red);
            }
        }
        void OnMouseMove(object sender, MouseEventArgs e)
        {
            if (iOper == 1) return;
            FrameworkElement element = sender as FrameworkElement;
            if (trackingMouseMove)
            {
                //计算位置
                double deltaV = e.GetPosition(null).Y - mousePosition.Y;
                double deltaH = e.GetPosition(null).X - mousePosition.X;
                double newTop = deltaV + (double)element.GetValue(Canvas.TopProperty);
                double newLeft = deltaH + (double)element.GetValue(Canvas.LeftProperty);
                //GetValue();SetValue();
                element.SetValue(Canvas.TopProperty, newTop);
                element.SetValue(Canvas.LeftProperty, newLeft);

                mousePosition = e.GetPosition(null);
            }
        }
        void OnMouseUp(object sender, MouseButtonEventArgs e)
        {
            if (iOper == 1) return;
            FrameworkElement element = sender as FrameworkElement;
            trackingMouseMove = false;
            element.ReleaseMouseCapture();//释放鼠标

            mousePosition.X = mousePosition.Y = 0;
            element.Cursor = null;
            Line line = (Line)element;//失去焦点
            line.Stroke = new SolidColorBrush(Colors.White);
        }
    }
}

源码：https://files.cnblogs.com/greatverve/SilverlightDrawDrag.rar