Move form with mouse movement using mouse down event C#.NET

Sometimes due to design requirement we need to create a border less form or a custom border around the form.  In case of default border the movement of form on mouse down is handled internally we do not need to write any code for this. But if we create a custom border or a border-less form then in that case we need to write a custom code to handle form movement using mouse. Here is the C# code to handle form movement on mouse down. 

using System.Runtime.InteropServices;

const int HT_CAPTION = 0x2;
const int WM_NCLBUTTONDOWN = 0xA1;

[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, MouseEventArgs e)
{
  if (e.Button == MouseButtons.Left)
  {
    ReleaseCapture();
    SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
  }
}

Here Form1 is a border-less form and by using above code Form1 will move with mouse down movement.

Similarly below is the case for custom border or any control on which we need the movement of form with mouse move. Here border_panel is panel control and in its mouse down event form movement is handled.

private void border_panel_mousedown(object sender, MouseEventArgs e)

{

 if (e.Button == MouseButtons.Left)
  {
    ReleaseCapture();
    SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
  }

}

In the above code user32.dll is included in the project. SendMessage and ReleaseCapture methods of user32.dll are used.