c#拖动无状态栏窗体

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



namespace myQQ
{
    public partial class MainForm : Form
    {
        Point mouseOff;         //记录鼠标指针的坐标
        bool leftFlag; 


   
        public MainForm()
        {
            InitializeComponent();
        }

        private void MainForm_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                mouseOff = new Point(-e.X, -e.Y); //得到变量的值
                leftFlag = true;                  //点击左键按下时标注为true;
            }



        }

        private void MainForm_MouseMove(object sender, MouseEventArgs e)
        {
            if (leftFlag)
            {
                Point mouseSet = Control.MousePosition;
                mouseSet.Offset(mouseOff.X, mouseOff.Y);  //设置移动后的位置
                Location = mouseSet;
            }
        }

        private void MainForm_MouseUp(object sender, MouseEventArgs e)
        {
            if (leftFlag)
            {
                leftFlag = false;//释放鼠标后标注为false;
            }
        }