画直线小程序需要改进，来看看吧
谁来帮我看看我的C#小程序
悬赏分：20 - 离问题结束还有 14 天 6 小时
编了一个画直线的小程序，我的思想是这样的，点了画直线按钮后，再按下鼠标就开始画线，不要松开鼠标键拖动的过程中会产生一条直线。松开鼠标后直线确定。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace DrawLine
{
public class Form1 : Form
{
bool stmove=false;//判断MouseMove操作是否开始
int x1,y1,x2,y2;//声明线的起点和终点坐标
bool start=false;
Graphics g;
Button btn;
Pen pen;
public Form1()
{
this.SuspendLayout();
pen = new Pen(Color.Red, 2);
btn = new Button();
btn.Text = "画直线 ";
this.Controls.Add(btn);
this.ResumeLayout();
btn.Click += new EventHandler(btn_Click);
this.MouseDown += new MouseEventHandler(Form1_MouseDown);
this.MouseUp += new MouseEventHandler(Form1_MouseUp);
this.MouseMove += new MouseEventHandler(Form1_MouseMove);
}
private void btn_Click(object sender,EventArgs e)
{
start = true;
g = this.CreateGraphics();
}
private void Form1_MouseDown(object sender,MouseEventArgs e)
{
if(start)
{
stmove = true;
x1=e.X;
y1=e.Y;
}
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (stmove)
{
g.Clear(this.BackColor);
x2 = e.X;
y2 = e.Y;
g.DrawLine(pen, x1, y1, x2, y2);
}
}
private void Form1_MouseUp(object sender,MouseEventArgs e)
{
if(start)
{
y2 = e.Y;
x2 = e.X;
g.DrawLine(pen,x1,y1,x2,y2);
stmove = false;
}
}
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
}
我发现一个问题就是画完第一调直线后再画第2条，第一条就没了，怎么解决这个问题。
[解决办法]
public partial class Form5 : Form
{
public Form5()
{
InitializeComponent();
}
private ArrayList drawingList = new ArrayList();
private Line currentLine = null;
private void Form5_MouseDown(object sender, MouseEventArgs e)
{
currentLine = new Line(new Point(e.X, e.Y));
}
private void Form5_MouseUp(object sender, MouseEventArgs e)
{
if (currentLine != null)
{
currentLine.MouseMove(new Point(e.X,e.Y));
drawingList.Add(currentLine);
currentLine = null;
this.Invalidate();
}
}
private void Form5_MouseMove(object sender, MouseEventArgs e)
{
if (currentLine != null && e.Button == MouseButtons.Left)
{
currentLine.MouseMove(new Point(e.X, e.Y));
this.Invalidate();
}
}
private void Form5_Paint(object sender, PaintEventArgs e)
{
foreach (Line line in drawingList)
{
line.Draw(e.Graphics);
}
if (currentLine != null)
{
currentLine.Draw(e.Graphics);
}
}
}
public class Line
{
private Point startPoint = new Point(0,0);
private Point endPoint= new Point(0,0);
public void MouseMove(Point p)
{
endPoint = p;
}
public Line(Point p)
{
startPoint = p;
}
public void Draw(Graphics g)
{
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
g.DrawLine(Pens.Black, startPoint, endPoint);
}
}
