c# 移动winform窗体

c# winform窗体，点击窗体标题头可以拖动，如果鼠标点击在里面的panel的时候就没有这个效果了，以下实现拖动的方法。

public class FormBase: Form
    {
        [DllImport("user32.dll")]  //需添加using System.Runtime.InteropServices
        public static extern bool ReleaseCapture();
        [DllImport("user32.dll")]
        public static extern bool SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);
        public const int WM_SYSCOMMAND = 0x0112;
        public const int SC_MOVE = 0xF010;
        public const int HTCAPTION = 0x0002;    


        public FormBase()
        {
            this.MouseDown += Form_Base_MouseDown;
        }

       

        private void Form_Base_MouseDown(object sender, MouseEventArgs e)
        {
            ReleaseCapture();
            SendMessage(this.Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0);

        }
    }