C#画图求助，努力思考就是不成功，求教求教

Question

做一个类似windows画图工具一样的东东，绘制直线、矩形之类的
拿绘制直线为例，鼠标左键按下时，移动鼠标开始绘制:
public partial class 画图 : Form
{
        Graphics g1;
        Point lastpoint;
        enum PaintType { Pencil = 1, Line, Rectangle, Ellipse, Polygon};
        PaintType painttype = PaintType.Pencil;        ArrayList Path = new ArrayList();     //存放绘制路径         
        Pen mypen = new Pen(Color.Black);     //画笔
        GraphicsPath gp = new GraphicsPath();
                 
        public 画图()
        {
            InitializeComponent();
            g1 = pictureBox1.CreateGraphics();
        }        private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {          
            lastpoint = new Point(e.X, e.Y);       //生成起点
        }         private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
             //直线
            if (painttype == PaintType.Line)
            {
                if (e.Button == MouseButtons.Left)
                {
                    g1.Clear(Color.White);       //清除上次绘制痕迹
                    Point currentpoint = new Point(e.X, e.Y);
                    g1.DrawLine(mypen, lastpoint, currentpoint);  //绘制
                    gp.AddLine(lastpoint, currentpoint);       //生成绘制路径
                }
                
            } 
        }        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
        {
            Path.Add(gp);        //保存路径
        }
         
        private void pictureBox1_Paint(object sender, PaintEventArgs e)
        {
            foreach (GraphicsPath i in Path)  
            {
                g1.DrawPath(mypen,i);             //绘制所有保存的路径
            }         
        }
 }程序大概是这个样子，想法是用ArrayList保存从前绘制的路径，以便在每次Clear()清除后重绘画面，不然每次画完的线都会消失。但是这样写了没有效果。
小弟初学c#一个月，老师让做这个画图，快逼疯了！！！！ 请高手指点迷津。

Answer 1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;namespace WindowsApplication5
{
    public partial class Form1 : Form
    {
        GraphicsPath gp = new GraphicsPath();
        Point lastpoint;
        Point currentpoint;
        Pen mypen = new Pen(Color.Black);           
        
        public Form1()
        {
            InitializeComponent();
            
        }        Bitmap Cache1;
        
        private void Form1_Load(object sender, EventArgs e)
        {
            Cache1 = new Bitmap(this.ClientSize.Width, this.ClientSize.Height);
            Graphics g = Graphics.FromImage(Cache1);
            g.Clear(Color.FromArgb(255,255,255));
            g.Dispose();
            
        }        private void Form1_SizeChanged(object sender, EventArgs e)
        {        }        private void Form1_ClientSizeChanged(object sender, EventArgs e)
        {
            Cache1 = new Bitmap(this.ClientSize.Width, this.ClientSize.Height);
            Graphics g = Graphics.FromImage(Cache1);
            g.Clear(Color.FromArgb(255, 255, 255));
            g.Dispose();
            
        }        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            lastpoint = new Point(e.X, e.Y);
        }        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                
                currentpoint = new Point(e.X, e.Y);
                Graphics g=this.CreateGraphics();
                g.DrawImageUnscaled(Cache1, 0, 0);
                g.DrawLine(mypen, lastpoint, currentpoint);
                g.Dispose();
            } 
                
        }        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            gp.AddLine(lastpoint, currentpoint);
            Graphics g = Graphics.FromImage(Cache1);
            g.DrawPath(mypen, gp);
        }        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.DrawImageUnscaled(Cache1,0,0);
        }
    }
}
拿着玩去吧...^_^

Answer 2

我只是帮你解决图象的闪动,以及无法清除的问题.其实你的思路没有问题..
希望你参考我提供的思路来解决问题,直说了把继续用你的ArrayList...

Answer 3

实现了一些简单的
主要绘制两部分，一部分是pictureBox中的Image，另一个是pictureBox
在pictureBox.Image中绘制的画面是不会消失的，看效果吧！
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace WindowsApplication43
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        /// <summary>
        /// 鼠标最后按下的位置
        /// </summary>
        Point lastPoint = Point.Empty;        private enum PaintType { Pencil = 1, Line, Rectangle, Ellipse, Polygon };
        PaintType paintType = PaintType.Pencil;         private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {
            lastPoint = e.Location;
        }        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
        {
            pictureBox1.Refresh();
            Graphics vGraphics = Graphics.FromImage(pictureBox1.Image); // 直接绘制到Image中
            switch (paintType)
            {
                case PaintType.Pencil:
                    break;
                case PaintType.Line:
                    vGraphics.DrawLine(Pens.Black, lastPoint, e.Location);
                    break;
                case PaintType.Ellipse:
                    vGraphics.DrawEllipse(Pens.Black, Rectangle.FromLTRB(
                        lastPoint.X, lastPoint.Y,
                        e.Location.X, e.Location.Y));
                    break;
                case PaintType.Rectangle:
                    vGraphics.DrawRectangle(Pens.Black, Rectangle.FromLTRB(
                        lastPoint.X, lastPoint.Y, 
                        e.Location.X,  e.Location.Y));
                    break;
            }
            vGraphics.Dispose();
            pictureBox1.Refresh();
            lastPoint = Point.Empty;
        }        private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
            if (lastPoint == Point.Empty) return; // 没有按下
            pictureBox1.Refresh(); // 刷新界面
            Graphics vGraphics = pictureBox1.CreateGraphics();
            switch (paintType)
            {
                case PaintType.Pencil:
                    break;
                case PaintType.Line:
                    vGraphics.DrawLine(Pens.Black, lastPoint, e.Location);
                    break;
                case PaintType.Ellipse:
                    vGraphics.DrawEllipse(Pens.Black, Rectangle.FromLTRB(
                        lastPoint.X, lastPoint.Y,
                        e.Location.X, e.Location.Y));
                    break;
                case PaintType.Rectangle:
                    vGraphics.DrawRectangle(Pens.Black, Rectangle.FromLTRB(
                        lastPoint.X, lastPoint.Y,
                        e.Location.X, e.Location.Y));
                    break;
            } 
            vGraphics.Dispose();
        }        private void Form1_Load(object sender, EventArgs e)
        {
            pictureBox1.Image = new Bitmap(pictureBox1.Width, pictureBox1.Height);
            Graphics vGraphics = Graphics.FromImage(pictureBox1.Image);
            vGraphics.FillRectangle(Brushes.White, vGraphics.ClipBounds);
            vGraphics.Dispose();            int i = 0;
            foreach (string vName in Enum.GetNames(typeof(PaintType)))
            {
                RadioButton vRadioButton = new RadioButton();
                vRadioButton.Parent = this;
                vRadioButton.Text = vName;
                vRadioButton.Click += new EventHandler(radioButton_Click);
                vRadioButton.Tag = Enum.GetValues(typeof(PaintType)).GetValue(i);
                if (i == 0) vRadioButton.PerformClick(); // 默认选第一个
                vRadioButton.Top = (i++) * 30;
            }
        }        private void radioButton_Click(object sender, EventArgs e)
        {
            paintType = ((PaintType)((RadioButton)sender).Tag);
        }
    }
}

Answer 4

你得到了画图的坐标，你要显示，你至少也得refresh一下，或是invalidate啊，要不怎么通知Picturebox画图。
用链表保存位置信息是肯定没错的，只是全部重画会有闪烁的问题。

Answer 5

楼主报E-mail地址，或者联系[email protected]；C#源代码提供。

Answer 6

线连接的问题已经解决，用ArrayList的方法我大概想清了，继续努力学习 Thx all.^^