WPF中RichTextBox内的游标位置

Question

I am developing a small WPF application, which has multiple tabs in it. I have a status bar in the bottom; the requirement is to show linenumber and column of the cursor. So when the user changes the cursor position, linenumber and column has to get updated automatically. Here is the code where I add RichTextBox; the code which calculates the linenumber and column is in the KeyDown event handler, but this event never gets called. Which event should I handle to get the cursor linenumber and column?

private void AddTabitem(string filePath, mode fileMode)
{
    if (fileMode == mode.openFile)
    {
        if (File.Exists(filePath))
        {
            RichTextBox mcRTB = new RichTextBox();
            mcRTB.KeyDown += new KeyEventHandler(LineNumber);
//rest of the code goes here
        }
    }
}
mcRTB.KeyDown += new KeyEventHandler(LineNumber);

private void LineNumber(object sender, KeyEventArgs e)
{          
    TextPointer tp1 = rtbList[EditorTabcontrol.SelectedIndex].Selection.Start.GetLineStartPosition(0);
    TextPointer tp2 = rtbList[EditorTabcontrol.SelectedIndex].Selection.Start;

    int column = tp1.GetOffsetToPosition(tp2);

    int someBigNumber = int.MaxValue;
    int lineMoved, currentLineNumber;
    rtbList[EditorTabcontrol.SelectedIndex].Selection.Start.GetLineStartPosition(-someBigNumber, out lineMoved);
    currentLineNumber = -lineMoved;
    string LineColumnLabel;

    //LineColumnLabel.Content = "Line: " + currentLineNumber.ToString() + " Column: " + column.ToString();
    LineColumnLabel = "Line: " + currentLineNumber.ToString() + " Column: " + column.ToString();        
}

Answer 1

There is a standard example to your task at MSDN ( http://msdn.microsoft.com/en-us/library/system.windows.controls.richtextbox.caretposition%28v=vs.110%29.aspx ). Please note, that in this context 'cursor' is called a 'caret'. Sample from MSDN follows:

// Create a new FlowDocument, and add 3 paragraphs.
FlowDocument flowDoc = new FlowDocument();
flowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 1"))); 
flowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 2"))); 
flowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 3")));
// Set the FlowDocument to be the content for a new RichTextBox.
RichTextBox rtb = new RichTextBox(flowDoc);

// Get the current caret position.
TextPointer caretPos = rtb.CaretPosition;

// Set the TextPointer to the end of the current document.
caretPos = caretPos.DocumentEnd;

// Specify the new caret position at the end of the current document.
rtb.CaretPosition = caretPos;

Answer 2

use this code to find Line and position

WPF

  "<Label x:Name="LabellineNr" Content="line#" BorderThickness="1" BorderBrush="DarkGray" />
  "<Label x:Name="LabelColumnNr" Content="Column#" BorderThickness="1" BorderBrush="DarkGray"/>

C# code

    private int privLineID = 1; 
    public int LineID
    {
        get { return privLineID; }
        set 
        { 
            privLineID = value;
            LabellineNr.Content = "Line: " + value;
        }
    }

    private int privColumnID = 1; 
    public int ColumnID
    {
        get { return privColumnID; }
        set 
        { 
            privColumnID = value;
            LabelColumnNr.Content = "Column: " + value;
        }
    }
    private int LineNumber()
    {
        TextPointer caretLineStart = RichTextControl.CaretPosition.GetLineStartPosition(0);
        TextPointer p = RichTextControl.Document.ContentStart.GetLineStartPosition(0);
        int currentLineNumber = 1;

        while (true)
        {
            if (caretLineStart.CompareTo(p) < 0)
            {
                break;
            }
            int result;
            p = p.GetLineStartPosition(1, out result);
            if (result == 0)
            {
                break;
            }
            currentLineNumber++;
        }
        return currentLineNumber;
    }

    private int ColumnNumber()
    {
        TextPointer caretPos = RichTextControl.CaretPosition;
        TextPointer p = RichTextControl.CaretPosition.GetLineStartPosition(0);
        int currentColumnNumber = Math.Max(p.GetOffsetToPosition(caretPos) - 1, 0);

        return currentColumnNumber;
    }