c# winform 用鼠标画拉出来的虚线框,鼠标框选边框效果

用鼠标画拖出来虚线框
只想单纯的画出一个矩形框

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace AllTest
{
	public partial class Form11 : Form
	{
		bool MouseIsDown = false;
		Rectangle MouseRect = Rectangle.Empty; 
		public Form11()
		{
			InitializeComponent();
			this.MouseDown += new MouseEventHandler(frmMain_MouseDown);
			this.MouseMove += new MouseEventHandler(frmMain_MouseMove);
			this.MouseUp += new MouseEventHandler(frmMain_MouseUp); 
		}
		void frmMain_MouseUp(object sender, MouseEventArgs e)
		{
			this.Capture = false;
			Cursor.Clip = Rectangle.Empty;
			MouseIsDown = false;
			DrawRectangle();
			MouseRect = Rectangle.Empty;
		}
		void frmMain_MouseMove(object sender, MouseEventArgs e)
		{
			if (MouseIsDown)
				ResizeToRectangle(e.Location);
		}
		void frmMain_MouseDown(object sender, MouseEventArgs e)
		{
			MouseIsDown = true;
			DrawStart(e.Location);
		}
		private void ResizeToRectangle(Point p)
		{
			DrawRectangle();
			MouseRect.Width = p.X - MouseRect.Left;
			MouseRect.Height = p.Y - MouseRect.Top;
			DrawRectangle();
		}
		private void DrawRectangle()
		{
			Rectangle rect = this.RectangleToScreen(MouseRect);
			ControlPaint.DrawReversibleFrame(rect, Color.White, FrameStyle.Dashed);
		}
		private void DrawStart(Point StartPoint)
		{
			this.Capture = true;
			Cursor.Clip = this.RectangleToScreen(new Rectangle(0, 0, ClientSize.Width, ClientSize.Height));
			MouseRect = new Rectangle(StartPoint.X, StartPoint.Y, 0, 0);
		} 
	}
}

在鼠标按下事件里写（一定是鼠标按下事件MouseDown 因为我的参数e是鼠标数据对象

（不过你也可以传坐标））

MouseIsDown = true;

DrawStart(e.Location);

在鼠标移动（MouseMove）事件里写

if (MouseIsDown)

ResizeToRectangle(e.Location);

在鼠标释放（MouseUp）事件里写

this.Capture = false;

Cursor.Clip = Rectangle.Empty;

MouseIsDown = false;

DrawRectangle();

MouseRect = Rectangle.Empty;

这样不会覆盖原来的控件,不会重绘控件

如果是加Panel的话

把DrawStart()方法里的Cursor.Clip = this.RectangleToScreen(this.Bounds);

改为Cursor.Clip = this.RectangleToScreen(this.panel1.ClientRectangle));

this.Capture = true;改为 this.panel1.Capture = true;

MouseUp里的 this.Capture = false;改为

this.panel1.Capture = false;

这是设置鼠标筐选时鼠标的移动区域 和控件对鼠标的捕获

Cursor.Clip = this.RectangleToScreen(this.Bounds);

这是设置鼠标筐选时鼠标的移动区域 根据你的需要自己去设置

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