c# 怎么画用鼠标拉出来的虚线框????

Question

想画那个十分常见的用鼠标拖出来虚线框，   
  我的panel里原来画了一个几何模型，   
  如果我在ondraw里面画虚线框的画，不是把原来的模型也重画了一遍吗？   
只想单纯的画出一个矩形框,新手,大虾见谅!!!

Answer 1

刚看了你的问题 写了一个！命名空间
using System.Drawing;定义两个变量
bool MouseIsDow=false;
Rectangle MouseRect = Rectangle.Empty;定义三个方法
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(this.Bounds);
   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;这样就没有重绘控件 

Answer 2

看了你的问题 写了一个！命名空间
using System.Drawing;定义两个变量
bool MouseIsDow=false;
Rectangle MouseRect = Rectangle.Empty;定义三个方法
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(this.Bounds);
   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;这样就没有重绘控件 

Answer 3

MouseIsDown 
我定义时写错了
MouseIsDow

Answer 4

这是我这边试的
没问题哦~
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace Probation
{
    public partial class frmMain : Form
    {
        bool MouseIsDown = false;
        Rectangle MouseRect = Rectangle.Empty; 
        public frmMain()
        {
            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); 
        } 
    }
}

Answer 5

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace WindowsApplication1
{
    public partial class Form1 : Form
    {        public Form1()
        {
            InitializeComponent();
        }        bool MouseIsDown = false;
        Rectangle MouseRect = Rectangle.Empty;        private void panel1_MouseUp(object sender, MouseEventArgs e)
        {
            this.Capture = false;
            Cursor.Clip = Rectangle.Empty;
            MouseIsDown = false;
            DrawRectangle();
            MouseRect = Rectangle.Empty;
        }        private void panel1_MouseMove(object sender, MouseEventArgs e)
        {
            if (MouseIsDown)
                ResizeToRectangle(e.Location);
        }        private void panel1_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.Red, FrameStyle.Thick);
        }        private void DrawStart(Point StartPoint)
        {
            this.Capture = true;
            Cursor.Clip = this.RectangleToScreen(this.Bounds);
            MouseRect = new Rectangle(StartPoint.X, StartPoint.Y, 0, 0);
        }    }
            
}
这个哪错了吗? 真晕...就过家个Panel

Answer 6

您找到问题了没?是不是panel控件的问题???

Answer 7

呵呵！
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;

Answer 8

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

Answer 9

你最好是写在 窗体里
如果要写Panel 里 就得继承Panel