C# GDI在控件上绘图的方法

本文以在chart控件上和窗体上画矩形为例子讲述了c# gdi在控件上绘图的方法。分享给大家供大家参考。具体方法如下：

具体的实现方法就不多解释了，备注很详细，代码也很简单。

主要功能代码如下：

using system;
using system.collections.generic;
using system.componentmodel;
using system.data;
using system.drawing;
using system.linq;
using system.text;
using system.windows.forms;
using system.io;
using system.configuration;

namespace wfapp2
{
  public partial class data : form
  {
    public data()
    {
      initializecomponent();
      //窗体
      g = this.creategraphics();
      //chart控件
      g2 = this.chart1.creategraphics();
    }
   
    public point firstpoint = new point(0, 0); //鼠标第一点 
    public point secondpoint = new point(0, 0); //鼠标第二点 
    public bool begin = false;  //是否开始画矩形 
    /// <summary>
    /// 在from上画矩形
    /// </summary>
    graphics g;

    /// <summary>
    /// 在chart1控件上画矩形
    /// </summary>
    graphics g2;

    /// <summary>
    /// 在窗体上按下鼠标事件
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void data_mousedown(object sender, mouseeventargs e)
    {
      begin = true;
      firstpoint = new point(e.x, e.y);
    }

    /// <summary>
    /// 在窗体上鼠标移动开始绘图
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void data_mousemove(object sender, mouseeventargs e)
    {
      if (begin)
      {
        //清除窗体绘图面,相当于刷新了一次窗体界面然后重新绘制
        g.clear(this.backcolor);
        //获取新的右下角坐标 
        secondpoint = new point(e.x, e.y);
        //获取两个数中的大者或小者
        int minx = math.min(firstpoint.x, secondpoint.x);
        int miny = math.min(firstpoint.y, secondpoint.y);
        int maxx = math.max(firstpoint.x, secondpoint.x);
        int maxy = math.max(firstpoint.y, secondpoint.y);

        //画框 
        g.drawrectangle(new pen(color.red), minx, miny, maxx - minx, maxy - miny);
        //controlpaint.drawreversibleframe(new rectangle(minx, miny, maxx - minx, maxy - miny),this.backcolor,framestyle.dashed);

      }
    }

    /// <summary>
    /// 鼠标松开停止绘图
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void data_mouseup(object sender, mouseeventargs e)
    {
      begin = false;
    }

    /// <summary>
    /// 在chart控件上移动鼠标绘图
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void chart1_mousemove(object sender, mouseeventargs e)
    {
      if (begin)
      {
        //重新在chart上面绘图，此处不能用clear方法，clear会清除整个绘图界面chart控件会被清除
        this.refresh();
        //获取新的右下角坐标 
        secondpoint = new point(e.x, e.y);
        int minx = math.min(firstpoint.x, secondpoint.x);
        int miny = math.min(firstpoint.y, secondpoint.y);
        int maxx = math.max(firstpoint.x, secondpoint.x);
        int maxy = math.max(firstpoint.y, secondpoint.y);

        //画矩形
        g2.drawrectangle(new pen(color.red), minx, miny, maxx - minx, maxy - miny);

      }
    }

    /// <summary>
    /// 鼠标松开停止绘图
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void chart1_mouseup(object sender, mouseeventargs e)
    {
      begin = false;
    }

    /// <summary>
    /// 在chart控件上按下鼠标
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void chart1_mousedown(object sender, mouseeventargs e)
    {
      begin = true;
      firstpoint = new point(e.x, e.y);
    }
  }
}

希望本文所述对大家的c#程序设计有所帮助