How to write and send text to mIRC in C#/Win32?

In a previous question, I asked how to send text to Notepad. It helped me immensely. For part 2, here's a simplified version of the same applied mIRC:

[DllImport("User32.dll", EntryPoint = "FindWindow")]
public static extern IntPtr FindWindow(String lpClassName, String lpWindowName);
[DllImport("user32.dll", EntryPoint = "FindWindowEx")]
public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
[DllImport("User32.dll")]
public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, string lParam);

IntPtr mainHandle = FindWindow("mIRC", null);
IntPtr serverHandle = FindWindowEx(mainHandle, new IntPtr(0), "MDIClient", null);
IntPtr chanHandle = FindWindowEx(serverHandle, new IntPtr(0), "mIRC_Channel", null);
IntPtr editHandle = FindWindowEx(chanHandle, new IntPtr(0), "Edit", null);

SendMessage(editHandle, 0x000C, 0, textBox1.Text);

This seems correct to me, except that it doesn't work! Is it that the window names are incorrect (MDIClient, mIRC_Channel, and Edit)? These are values I found on a web site by googling "FindWindowEx mIRC".

1.) What am I doing wrong in the above?

2.) For reference, in general is there an easy way to find all the Window names for use with FindWindowEx()?

From stackoverflow

• This code works for me (mirc 6.31):

  IntPtr mainHandle = FindWindow("mIRC", null);
  IntPtr serverHandle = FindWindowEx(mainHandle, new IntPtr(0), "MDIClient", null);  
  IntPtr chanHandle = FindWindowEx(serverHandle, new IntPtr(0), "mIRC_Channel", null);  
  IntPtr editHandle = FindWindowEx(chanHandle, new IntPtr(0), "richEdit20A", null);
  SendMessage(editHandle, 0x000C, 0, "Hello World");
  

  Notice the changed window class (richedit20A instead of edit). Just found the correct class by using Spy++.

  As for the window handles, one possibility is to use the EnumWindows or EnumChildWindows API.