WPF TextBlock IsTextTrimmed 判断文本是否超出

　　　　private bool IsTextTrimmed(TextBlock textBlock)
        {
            Typeface typeface = new Typeface(
                textBlock.FontFamily,
                textBlock.FontStyle,
                textBlock.FontWeight,
                textBlock.FontStretch);

            FormattedText formattedText = new FormattedText(
                textBlock.Text,
                System.Threading.Thread.CurrentThread.CurrentCulture,
                textBlock.FlowDirection,
                typeface,
                textBlock.FontSize,
                textBlock.Foreground);

            formattedText.MaxTextWidth = textBlock.ActualWidth;

            bool isTrimmed = formattedText.Height > textBlock.ActualHeight ||
                             formattedText.Width >textBlock.MaxTextWidth; 
　　　　　　　return isTrimmed;
　　　　 }