【C#】[窗体]窗体无标题栏拖动

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;

namespace 窗体拖动
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
           this.FormBorderStyle=FormBorderStyle.None;//设置无标题栏
        }

        //--------窗体拖动---------

        Point mouseOff;//鼠标移动位置变量

        bool leftFlag;//标签是否为左键

        //在窗体上按下发生事件
        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)//如果按下的是鼠标左键
            {
                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;
            }

        }
        //鼠标移动的事件
        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {

            if (leftFlag)//如果鼠标左键是按下的状态
            {
                Point mouseSet = Control.MousePosition;
                mouseSet.Offset(mouseOff.X, mouseOff.Y);  //设置移动后的位置
                Location = mouseSet;
            }

        }
        //鼠标松开的事件
        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (leftFlag)//如果鼠标左键是松开的状态
            {
                leftFlag = false;//释放鼠标后标注为false;
            }

        }
    }
}