C#/WPF 计算字串的真实长度 （转载）

 private double MeasureTextWidth(string text, double fontSize, string fontFamily)
        {
            FormattedText formattedText = new FormattedText(
            text,
            System.Globalization.CultureInfo.InvariantCulture,
            FlowDirection.LeftToRight,
            new Typeface(fontFamily.ToString()),
            fontSize,
            Brushes.Black
            );
            return formattedText.WidthIncludingTrailingWhitespace;
        }