c# sendmessage control to scroll

Declare some constants:
private const int WM_SCROLL = 276; // Horizontal scroll
private const int WM_VSCROLL = 277; // Vertical scroll
private const int SB_LINEUP = 0; // Scrolls one line up
private const int SB_LINELEFT = 0;// Scrolls one cell left
private const int SB_LINEDOWN = 1; // Scrolls one line down
private const int SB_LINERIGHT = 1;// Scrolls one cell right
private const int SB_PAGEUP = 2; // Scrolls one page up
private const int SB_PAGELEFT = 2;// Scrolls one page left
private const int SB_PAGEDOWN = 3; // Scrolls one page down
private const int SB_PAGERIGTH = 3; // Scrolls one page right
private const int SB_PAGETOP = 6; // Scrolls to the upper left
private const int SB_LEFT = 6; // Scrolls to the left
private const int SB_PAGEBOTTOM = 7; // Scrolls to the upper right
private const int SB_RIGHT = 7; // Scrolls to the right
private const int SB_ENDSCROLL = 8; // Ends scroll

Add a using reference
using System.Runtime.InteropServices;

Declare external SendMessage:
[DllImport("user32.dll",CharSet=CharSet.Auto)]
private static extern int SendMessage(IntPtr hWnd, int wMsg,IntPtr wParam, IntPtr lParam);

Usage: 
If you have some textbox on the form...

SendMessage( Control Handle , WM Scroll Message, (IntPtr) Scroll Command ,IntPtr.Zero);

Scroll page up
SendMessage(textBox1.Handle,WM_VSCROLL,(IntPtr)SB_PAGEUP,IntPtr.Zero);

Scroll page down
SendMessage(textBox1.Handle,WM_VSCROLL,(IntPtr)SB_PAGEDOWN,IntPtr.Zero);

The DataGridView control has 2 sub-controls, a VScrollBar and a HScrollBar. If you want to do a scroll over a DataGridView you have to send the WM_VSCROLL or WM_HSCROLL message to the DataGridView handle, with wParam as the SB_xxxx value you want, and lParam as the scrollbar handle. 

Example: 
public void ScrollControlDown(DataGridView dataGridView) 
{ 
VScrollBar barraVertical = null; 

foreach (Control c in dataGridView.Controls) 
{ 
if (c is VScrollBar) barraVertical = (VScrollBar)c; 
} 

if (barraVertical != null) 
{ 
SendMessage(dataGridView.Handle, WM_VSCROLL, (IntPtr)SB_LINEDOWN, barraVertical.Handle); 
SendMessage(dataGridView.Handle, WM_VSCROLL, (IntPtr)SB_ENDSCROLL, barraVertical.Handle); 
} 
} 

This method requires the DataGridView's ScrollBars property shows the scrollbar over you are going to do the programatical scroll. If you want to send WM_VSCROLL, ScrollBars property must be set to Both or Vertical. If you want to send WM_HSCROLL, ScrollBars propery must be set to Both or Horizontal.