title: SendMessage WM_SETTEXT to TextBox doesn't trigger TextChanged Event
body: <p>I have code that gets the handle to a textbox control and uses the windows API to change the text.
  The TextChanged event doesn't fire when the text is updated.</p>
  
  <p>Is there a way to fire the TextBox.TextChanged event using the Windows API?</p>
  
  <p><strong>[Update]</strong><br />
  I think the reason the event doesn't fire is because the textbox handle is sent though a DCOM interface. 
  The program is a National Instruments TestStand shell written in c# and uses the NI TestStand COM object for the core functionality. In the TS sequence file (a sort of TS script language) I created an object reference for the textbox handle and set it using the TS api in the shell form's load event. After that I send the handle to my c# DLL. I use SendMessage to update the textbox and that works good. The problem is that the TextChanged event doesn't fire. </p>
  
  <p>I tried using the TS interface to send the textbox and the TextChanged delegate and I couldn't get it to work. I think there is an AppDomain issue doing that through the TS COM object.</p>