Move window/form without Titlebar in C#

using System.Runtime.InteropServices;

public const int WM_NCLBUTTONDOWN = 0xA1;
public const int HT_CAPTION = 0x2;
[DllImportAttribute("user32.dll")]
public static extern int SendMessage(IntPtr hWnd,
　　　　　　　　int Msg, int wParam, int lParam);
[DllImportAttribute("user32.dll")]
public static extern bool ReleaseCapture();

private void Form1_MouseDown(object sender,
　　　　　 System.Windows.Forms.MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
　ReleaseCapture();
　SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
}}