SendKeys

This is a method for sending one or more keystrokes to the active window.
This should only be used as a last resort as it is not 100% secure and relies on the user not interrupting the macro.
SendKeys allows you to send keystrokes to the currently active window and is often used to control applications that do not support any other form of communication.
An example of such an application is NotePad.

Simple Example

This example opens NotePad and sends a line of data before saving the file.

Public Sub OpenNotePad 
Dim vReturn As Variant 
   vReturn = Shell("NotePad.exe", vbNormalFocus) 
   AppActivate vReturn 
   Application.SendKeys "Copy Data.xls C:\", True 

'this sends an Enter
   Application.SendKeys "~", True 

'this sends an (Alt + F + A) to perform a (File > Save As) and then enters the filename "BATCH" and presses Enter
   Application.SendKeys "%FABATCH~", True 
End Sub 

Multiple Keys

You can abbreviate sending the same key several times by appending a number inside the brackets
This has not been tested yet !!

Application.SendKeys "{Up 6}" 

This sends a Ctrl + F1

Application.SendKeys "^{F1}" 

Example of joined up

Application.SendKeys "{TAB}{TAB}" 

Potential Problems

When using SendKeys you often find that not all the keys sent reach the dialog box although sending all the keys at once does not make a difference.

Application.SendKeys "{Esc}" 

Enter simulate Tab

Make the Enter simulate the Tab key

Sub Form_KeyPress (keyAscii as integer) 
   If KeyAscii = vbKeyReturn Then 
      SendKeys "{TAB}" 
      KeyAscii = 0 
   End If 
End Sub 

Reference Table