wpf richtextbox 检查插入符是否在最后一行或计算它有多少行

Question

我试图在富文本框中找出插入符是否位于最后一行。这可能吗？

注意：最后我还添加了：或计算它有多少行，这是因为在miscrosoft论坛中有一个用于检测插入符在哪一行的示例。

谢谢

Answer 1

请验证 msdn 链接

http:// Social.msdn.microsoft.com/Forums/en/wpf/thread/667b5d2a-84c3-4bc0-a6c0-33f9933db07f

如果您确实想知道插入符号的行号，您可以执行以下操作（可能需要一些调整）：

TextPointer caretLineStart = rtb.CaretPosition.GetLineStartPosition(0);
TextPointer p = rtb.Document.ContentStart.GetLineStartPosition(0);
int caretLineNumber = 1;

while (true)
{
    if (caretLineStart.CompareTo(p) < 0)
    {
        break;
    }

    int result;
    p = p.GetLineStartPosition(1, out result);

    if (result == 0)
    {
        break;
    }

    caretLineNumber++;
}

Answer 2

获取行数的代码：

Int32 CountDisplayedLines(RichTextBox rtb)
{
    Int32 result = -1;

    rtb.CaretPosition = rtb.Document.ContentStart;

    while (rtb.CaretPosition.GetLineStartPosition(++result) != null)
    {
    }

    return result;
}

Answer 3

我找到了解决办法。也许有更简单的方法，如果有请告诉我

    private void OnHasRtbReachedEnd(System.Windows.Controls.RichTextBox rtb)
    {
        TextPointer pointer1 = rtb.CaretPosition;
        int iCurrentLine = GetLineNumber(rtb);
        rtb.CaretPosition = rtb.Document.ContentEnd;
        int iLastLine = GetLineNumber(rtb);

        if (iCurrentLine == iLastLine)
        {
            if (!_bIsRtbMovingUpDown)
                MoveToNextDataGridRow();
            _bIsRtbMovingUpDown= false;
        }
        else
        {
            _bIsRtbMovingUpDown= true;
        }
        rtb.CaretPosition = pointer1;
    }

//这段代码来自
//http://social.msdn .microsoft.com/Forums/en/wpf/thread/667b5d2a-84c3-4bc0-a6c0-33f9933db07f

    private int GetLineNumber(System.Windows.Controls.RichTextBox rtb)
    {
        TextPointer caretLineStart = rtb.CaretPosition.GetLineStartPosition(0);
        TextPointer p = rtb.Document.ContentStart.GetLineStartPosition(0);
        int caretLineNumber = 1;

        while (true)
        {
            if (caretLineStart.CompareTo(p) < 0)
            {
                break;
            }

            int result;
            p = p.GetLineStartPosition(1, out result);

            if (result == 0)
            {
                break;
            }

            caretLineNumber++;
        }
        return caretLineNumber;

    }

Answer 4

我尝试了代码，但并不总是给出正确的结果。
一种聪明的方法是这样的

    int previousCursorPosition;
    private void RichTarget_KeyDown_1(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.Up || e.Key == Key.Down)
        {
            Xceed.Wpf.Toolkit.RichTextBox rich = (Xceed.Wpf.Toolkit.RichTextBox)sender;
            previousCursorPosition = rich.CaretPosition.GetOffsetToPosition(rich.CaretPosition.DocumentStart);
        }
    }
    private void RichTextBox_KeyUp_1(object sender, KeyEventArgs e)
    {

            if (e.Key == Key.Up)
            {
                Xceed.Wpf.Toolkit.RichTextBox rich = (Xceed.Wpf.Toolkit.RichTextBox)sender;

                if (previousCursorPosition == rich.CaretPosition.GetOffsetToPosition(rich.CaretPosition.DocumentStart))
                {
                     //do your staff

                }

            }
            else if (e.Key == Key.Down)
            {
                Xceed.Wpf.Toolkit.RichTextBox rich = (Xceed.Wpf.Toolkit.RichTextBox)sender;
                if (previousCursorPosition == rich.CaretPosition.GetOffsetToPosition(rich.CaretPosition.DocumentStart))
                {
                    //do your staff
                }
            }


    }