嗨,我试着用C中的鼠标在窗体上绘制一个橡皮矩形。

问题

1)鼠标释放后,矩形消失。[我想把它留在表格上]

2)我还需要找到绘制矩形的四个点的坐标。

3)必要时,我还需要删除矩形以绘制新的矩形。

形式:

代码

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

namespace rubberbandrectangle

{

public partial class Form1 : Form

{

Boolean bHaveMouse;

Point ptOriginal = new Point();

Point ptLast = new Point();

public Form1()

{

InitializeComponent();

}

private void Form1_MouseDown(object sender, MouseEventArgs e)

{

bHaveMouse = true;

ptOriginal.X = e.X;

ptOriginal.Y = e.Y;

ptLast.X = -1;

ptLast.Y = -1;

}

private void MyDrawReversibleRectangle(Point p1, Point p2)

{

Rectangle rc = new Rectangle();

p1 = PointToScreen(p1);

p2 = PointToScreen(p2);

if (p1.X < p2.X)

{

rc.X = p1.X;

rc.Width = p2.X - p1.X;

}

else

{

rc.X = p2.X;

rc.Width = p1.X - p2.X;

}

if (p1.Y < p2.Y)

{

rc.Y = p1.Y;

rc.Height = p2.Y - p1.Y;

}

else

{

rc.Y = p2.Y;

rc.Height = p1.Y - p2.Y;

}

ControlPaint.DrawReversibleFrame(rc,

Color.Red, FrameStyle.Dashed);

}

private void Form1_MouseUp(object sender, MouseEventArgs e)

{

bHaveMouse = false;

if (ptLast.X != -1)

{

Point ptCurrent = new Point(e.X, e.Y);

MyDrawReversibleRectangle(ptOriginal, ptLast);

}

ptLast.X = -1;

ptLast.Y = -1;

ptOriginal.X = -1;

ptOriginal.Y = -1;

}

private void Form1_MouseMove(object sender, MouseEventArgs e)

{

Point ptCurrent = new Point(e.X, e.Y);

if (bHaveMouse)

{

if (ptLast.X != -1)

{

MyDrawReversibleRectangle(ptOriginal, ptLast);

}

ptLast = ptCurrent;

MyDrawReversibleRectangle(ptOriginal, ptCurrent);

}

}

private void Form1_Load(object sender, EventArgs e)

{

MouseDown += new MouseEventHandler(Form1_MouseDown);

MouseUp += new MouseEventHandler(Form1_MouseUp);

MouseMove += new MouseEventHandler(Form1_MouseMove);

bHaveMouse = false;

}

}

}

谢谢你的阅读