using System;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.InteropServices;

using System.Text;

using System.Windows.Forms;

namespace ProductKeyGenerator

{

public static class TextBoxExtensions

{

private const int ECM_FIRST = 0x1500;

[DllImport("user32.dll", CharSet=CharSet.Unicode, EntryPoint = "SendMessageW")]

private static extern int SendMessage(IntPtr hwnd, int wMsg, int wParam,String lParam);

[DllImport("user32.dll", CharSet = CharSet.Unicode, EntryPoint = "SendMessageW")]

private static extern int SendMessage(IntPtr hwnd, int wMsg,out String wParam,ref String lParam);

//#define EM_SETCUEBANNER (ECM_FIRST + 1) // Set the cue banner with the lParm = LPCWSTR

private const int EM_SETCUEBANNER = (ECM_FIRST + 1);

private const int EM_GETCUEBANNER = (ECM_FIRST+2);

public static void SetCueBanner(this TextBox tx, String banner)

{

SendMessage(tx.Handle, EM_SETCUEBANNER, 0,banner);

}

public static String GetCueBanner(this TextBox tx)

{

String value = "";

String result = new string(Enumerable.Repeat(' ', 32767).ToArray());

SendMessage(tx.Handle, EM_GETCUEBANNER, out value,ref result);

return result.Replace('\0', ' ').Trim();

}

}

}