Watermark TextBox in WinForms

Question

Can anyone point me to a good implementation of a basic Windows Forms TextBox that will initially show watermark text that disappears when the cursor enters it? I think I ca

Answer 1

[DllImport("user32.dll", CharSet = CharSet.Unicode)]
private static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, string lParam);

And the message constants:

private const uint EM_SETCUEBANNER = 0x1501;
private const uint CB_SETCUEBANNER = 0x1703;    // minimum supported client Windows Vista, minimum supported server Windows Server 2008

And imho the best way to implement it is as an extension method.
So for the TextBox control the syntax would be:

MyTextBox.CueBanner(false, "Password");

From the code:

public static void CueBanner(this TextBox textbox, bool showcuewhenfocus, string cuetext)
{
    uint BOOL = 0;
    if (showcuewhenfocus == true) { BOOL = 1; }

    SendMessage(textbox.Handle, EM_SETCUEBANNER, (IntPtr)BOOL, cuetext); ;
}