C# 窗体随鼠标移动

 public partial class NewMainUI : Form
    {
        private Point mouseOffset;
        public NewMainUI()
        {
            InitializeComponent();
        }

        private void UIBG_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                mouseOffset.X = e.X;
                mouseOffset.Y = e.Y;
            }
        }

        private void UIBG_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                Top = MousePosition.Y - mouseOffset.Y;
                Left = MousePosition.X - mouseOffset.X;
            }
        }