Form1：
C# code：
using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;

namespace yanshi
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

            
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
                Thread th = new Thread(new ThreadStart(dr));
                th.Start();
        }

        public void dr()
        {            
            int i = 0;
            Graphics g = this.CreateGraphics();
            Color col1 = Color.White;
            Color col2 = Color.Black;
            SolidBrush brus1 = new SolidBrush(col1);
            SolidBrush brus2 = new SolidBrush(col2);
            Rectangle rect = new Rectangle(0, 0, 0, 0);
            rect.Location = new Point(100, 400);
            rect.Width = 200;      //Set rect's width
            rect.Height = 200;     //set rect's height
            do
            {
                if (i % 2 == 0)
                {
                    g.FillRectangle(brus1, rect);//Drawing white for high voltage                     
                }
                else
                {
                    g.FillRectangle(brus2, rect);//Drawing black for low voltage
                }
                ys.AccurateTimer.AccurateSleep(50);
                i++;
            } while (i<1000);
        }
    }
}


ys.cs:
C# codeusing System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace ys
{
    public struct MSG    //structure MSG
    {
        public IntPtr handle;
        public uint msg;
        public IntPtr wParam;
        public IntPtr lParam;
        public uint time;
        public System.Drawing.Point p;

    }
    public class AccurateTimer
    {
        public static bool IsTimeBeginPeriod = false;

        const int PM_REMOVE = 0x0001;

        [DllImport("user32.dll", SetLastError = true)]
        private static extern bool PeekMessage(out MSG lpMsg, IntPtr hWnd, uint wMsgFilterMin,
           uint wMsgFilterMax, uint wRemoveMsg);

        [DllImport("user32.dll", SetLastError = true)]
        static extern bool TranslateMessage(ref MSG lpMsg);

        [DllImport("user32.dll", SetLastError = true)]
        static extern bool DispatchMessage(ref MSG lpMsg);

        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern bool QueryPerformanceCounter(ref Int64 count);

        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern bool QueryPerformanceFrequency(ref Int64 frequency);

        public static int GetTimeTick()
        {
            return Environment.TickCount;
        }

        public static void AccurateSleep(float DlayTime)
        {
            Int64 Frequency = 0;
            Int64 StartTime = 0;
            Int64 EndTime = 0;
            float PassedMSec = 0;
            MSG msg;
            AccurateTimer.QueryPerformanceCounter(ref StartTime);   //get start time
            AccurateTimer.QueryPerformanceFrequency(ref Frequency); //get cpu's frequency
            do
            {
                if (AccurateTimer.PeekMessage(out msg, IntPtr.Zero, 0, 0, PM_REMOVE))
                {
                    AccurateTimer.TranslateMessage(ref msg);
                    AccurateTimer.DispatchMessage(ref msg);
                }
                AccurateTimer.QueryPerformanceCounter(ref EndTime);
                PassedMSec = ((float)(EndTime - StartTime) / (float)Frequency) * 1000;
            } while (PassedMSec <= DlayTime);  // delay  DlayTime
        }
    }

}


就这两个，你们先看看效果，应该和我的一样问题：就是黑白在闪的时候，有一条东西从上而下的划过，肉眼能看清楚，像是以前黑白电视那种东西...能解决这个问题的，我估计只有超级高手了。
 
 

就算是先绘制完，存在虚拟画布上，然后再贴过去也是有这个问题存在

那有什么办法没？

显示器60hz刷新，我的20hz刷新比它少应该不会有问题才对啊