GtkSharp/gtk/TextBuffer.custom

public string Text {
	get {
		return GetText (StartIter, EndIter, false);
	}

	set {
		gtk_text_buffer_set_text (Handle, value, 
				System.Text.Encoding.Default.GetByteCount(value));
	}
}

public void Clear ()
{
	Delete (StartIter, EndIter);
}

public Gtk.TextIter GetIterAtOffset(int char_offset)
{
        Gtk.TextIter iter;

        gtk_text_buffer_get_iter_at_offset(Handle, out iter, char_offset);

        return iter;
}