WPF，在richtextbox

Question

我尝试在richtextbox中突出显示文字。 我用按钮点击事件。 这是我的代码。

结果..... 这是一种泡沫排序。

位置和目标位置是对的。

但是，突出显示的字符与位置不同。

之后，文字没有画上。

// print one line
this.rtb1.AppendText(this.IntToString(traceInfo.SortingNumbers));
this.rtb1.AppendText("\r\n");

ChangeTextColor(traceInfo.Position, traceInfo.TargetPosition);
private void ChangeTextColor(int position, int targetPosition)
    {
        int length;
        int pos = GetTextPositionAndLength(position, count, out length);

        TextRange textRange = new TextRange(rtb1.Document.ContentStart, rtb1.Document.ContentEnd);
        TextPointer startPointer = textRange.Start.GetPositionAtOffset(pos);
        TextPointer endPointer = textRange.Start.GetPositionAtOffset(pos + length);
        TextRange tr2 = new TextRange(startPointer, endPointer);
        tr2.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.Red));

        int pos2 = GetTextPositionAndLength(targetPosition, count, out length);
        TextRange textRange2 = new TextRange(rtb1.Document.ContentStart, rtb1.Document.ContentEnd);
        TextPointer startPointer2 = textRange2.Start.GetPositionAtOffset(pos2);
        TextPointer endPointer2 = textRange2.Start.GetPositionAtOffset(pos2 + length);
        TextRange tr4 = new TextRange(startPointer2, endPointer2);
        tr4.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.LightBlue)); 
   } 
    private int GetTextPositionAndLength(int position, int lineIndex, out int length)
    {
        //  First charcter position index of lineIndex 
        int richtTextLineIndex = GetFirstCharIndexFromLine(lineIndex);

        if (position == 0)
        {
            length = GetTextLength(0, lineIndex);
            return richtTextLineIndex;
        }
        int index = 0;
        int posIter = 0;
        string line = Line(lineIndex);

        length = 0;
        for (index = 0; index < line.Length; index++)
        {
            if (line[index] == ' ')
            {
                posIter++;
                if (posIter == position)
                {
                    index++;
                    length = GetTextLength(index, lineIndex);
                    break;
                }
            }
        }
        return index + richtTextLineIndex;
    }

}

我无法解决这个问题。 帮助我..请

Answer 1

将ChangeTextColor替换为：

    private void ChangeTextColor(int position, int targetPosition)
    {
        int length;
        var line = rtb1.Document.Blocks.ElementAt(count);
        TextRange lineRange = new TextRange(line.ContentStart, line.ContentEnd);


        int positionLeft = GetTextPositionAndLength(position, lineRange.Text, out length);

        TextPointer startPointerLeft = lineRange.Start.GetPositionAtOffset(positionLeft);
        TextPointer endPointerLeft = lineRange.Start.GetPositionAtOffset(positionLeft + length);
        TextRange selectRangeLeft = new TextRange(startPointerLeft, endPointerLeft);
        selectRangeLeft.ApplyPropertyValue(TextElement.ForegroundProperty,
            new SolidColorBrush(Colors.Red));

        int positionRight = GetTextPositionAndLength(targetPosition, lineRange.Text, out length);

        TextPointer startPointerRight = GetTextPointAt(lineRange.Start, positionRight - 1);
        TextPointer endPointerRight = GetTextPointAt(lineRange.Start, positionRight + length - 1);
        TextRange selectRangeRight = new TextRange(startPointerRight, endPointerRight);
        selectRangeRight.ApplyPropertyValue(TextElement.ForegroundProperty,
            new SolidColorBrush(Colors.LightBlue));

        Debug.WriteLine("Left text: " + selectRangeLeft.Text + "; Right text: " + selectRangeRight.Text);

        count++;
    }

并添加新方法：

    private static TextPointer GetTextPointAt(TextPointer from, int pos)
    {
        TextPointer ret = from;
        int i = 0;

        while ((i < pos) && (ret != null))
        {
            if ((ret.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.Text) || (ret.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.None))
                i++;

            if (ret.GetPositionAtOffset(1, LogicalDirection.Forward) == null)
                return ret;

            ret = ret.GetPositionAtOffset(1, LogicalDirection.Forward);
        }

        return ret;
    }

    private int GetTextPositionAndLength(int position, string line, out int length)
    {
        if (position == 0)
        {
            length = GetTextLength(0, line);
            return 0;
        }

        int index = 0;
        int posIter = 0;

        length = 0;
        for (index = 0; index < line.Length; index++)
        {
            if (line[index] == ' ')
            {
                posIter++;
                if (posIter == position)
                {
                    index++;
                    length = GetTextLength(index, line);
                    break;
                }
            }
        }
        return index;
    }

    private int GetTextLength(int index, string line)
    {
        int length = 0;
        for (int i = index; i < line.Length; i++)
        {
            if (line[i] == ' ')
            {
                break;
            }
            length++;
        }
        return length;
    }

它对我有用。希望，它有所帮助