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

namespace 绘图pen
{
    public partial class F : Form
    {
        public F()
        {
            InitializeComponent();
        }
        string sun = "";

        //F
        private void F_Load(object sender, EventArgs e)
        {

        }

        private Point mypen;
        bool l = false;
        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (sun == "")
            {

            }
            if (l)
            {
                Graphics g = p1.CreateGraphics();
                g.DrawLine(new Pen(new SolidBrush(Color.Red)), mypen, new Point(e.X, e.Y));
                mypen = new Point(e.X, e.Y);
            }
        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                l = true;
                mypen = new Point(e.X, e.Y);
            }
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            l = false;
        }



        //pi1
        private void pi1_Click(object sender, EventArgs e)
        {
            sun = "go1";
        }

        private void pictureBox1_Click(object sender, EventArgs e)
        {
            DialogResult result = colorDialog1.ShowDialog();
            if (result == DialogResult.OK)//确定事件响应
            {

            }

            if (result == DialogResult.Cancel)//取消事件响应
            {

            }
        }
    }
}

Graphics g = label1.CreateGraphics();             // 创建画板   
colorDialog1.ShowDialog();                        //打开颜色对话框
Pen p = new Pen(colorDialog1.Color,10);           //实例化画笔
g.DrawEllipse(p, 10, 15, 150, 90);                //画一个椭圆