/// <summary>
/// Ermittelt die Position des Carets für den angegebenen Punkt
/// </summary>
/// <param name="textBox">das Eingabefeld, dessen Caret-Position ermittelt werden soll</param>
/// <param name="point">der Punkt, für den die Caret-Position ermittelt werden soll</param>
/// <returns></returns>
public static int GetCaretIndexFromPoint(this TextBoxBase textBox, Point point)
{
Point actualPoint = textBox.PointToClient(point);
int index = textBox.GetCharIndexFromPosition(actualPoint);
if (index == textBox.Text.Length - 1)
{
Point caretPoint = textBox.GetPositionFromCharIndex(index);
if (actualPoint.X > caretPoint.X)
{
index += 1;
}
}
return(index);
}