Richtextbox lines count

问题

I'm developing a text editor in C#, and I'm trying to make a line count.

    private void updateNumberLabel()
    {
        Point pos = new Point(0, 0);
        int firstIndex = Document.GetCharIndexFromPosition(pos);
        int firstLine = Document.GetLineFromCharIndex(firstIndex);

        pos.X = ClientRectangle.Width;
        pos.Y = ClientRectangle.Height;

        int lastIndex = Document.GetCharIndexFromPosition(pos);
        int lastLine = Document.GetLineFromCharIndex(lastIndex);

        int actualLine = Document.GetLineFromCharIndex(actualPos);
        pos = Document.GetPositionFromCharIndex(lastIndex);

        if (lastLine != actualLine)
        {
            numberLabel.Text = "";
            for (int i = firstLine; i <= lastLine + 1; i++)
            {
                numberLabel.Text += i + 1 + "\n";
            }
        }
    }

It works fine and adds the number of lines while you write them, but if you delete one, it will only update if you delete or add one more line.

I want make it instantaneous. If you delete one, the count shall be decreased instantaneously.

回答1:

Maybe this is too easy, but what about that:

private void richTextBox1_TextChanged(object sender, EventArgs e)
{
  var lineCount = richTextBox.Lines.Count();
  numberLabel.Text = lineCount.ToString();
}

Make sure you assign it to the TextChanged event.

If this is not what you need, please add some more information what you are trying to achieve.

回答2:

I'm really late, but Lines is an array of string. Just get the length.

richTexBox.Lines.Length.ToString();

回答3:

Los799

Sorry for answering a "bit" late, I saw this question just now. But if the problem still stands, here's a simple way to count lines, just use a foreach loop:

int CountOfLines = 1;//1 because min 1 line is always in a text of a control, that has a Text property
foreach (char c in YourText)
            {
                if (c == '\r' | c == '\n')//these are all equal the ENTER key
                {
                    CountOfLines++;
                }
            }

You can also use foreach to count characters as well, but with foreach you can choose characters, that you don't want to be counted in the count of characters. For example:

int CountOfCharacters = 0;//0 because by default there are no characters in a textbox or label.
foreach (char c in YourText)
            {
                if (c != '\t' & c != '\n' & c != '\r')//in this example I want to count only the characters that are not an ENTER or a TAB.
                {
                    CountOfCharacters++;
                }
            }

Hope this helps you and everybody else, who's reading this, even if it's a bit late answer. :)

回答4:

I have found one open source and applied it to this problem.

I have confirmed that it works well and have implemented it.

RichTextBox Colums and Row

Simple Code( The link has a demo source.):

this.rtb.CursorPositionChanged += 
    new System.EventHandler(this.rtb_CursorPositionChanged);
this.rtb.SelectionChanged += 
    new System.EventHandler(this.rtb_SelectionChanged);
.
.
.
private void rtb_CursorPositionChanged(object sender, System.EventArgs e)
{
    int line = rtb.CurrentLine;
    int col = rtb.CurrentColumn;
    int pos = rtb.CurrentPosition;

    statusBar.Text = "Line " + line + ", Col " + col + 
                     ", Position " + pos;
}

private void rtb_SelectionChanged(object sender, System.EventArgs e)
{
    int start = rtb.SelectionStart;
    int end = rtb.SelectionEnd;
    int length = rtb.SelectionLength;

    statusBar.Text = "Start " + start + ", End " + end + 
                     ", Length " + length;
}

namespace Nik.UserControls
{
    public class RicherTextBox2 : System.Windows.Forms.RichTextBox
    {
        public event EventHandler CursorPositionChanged;

        protected virtual void OnCursorPositionChanged( EventArgs e )
        {
            if ( CursorPositionChanged != null )
                CursorPositionChanged( this, e );
        }

        protected override void OnSelectionChanged( EventArgs e )
        {
            if ( SelectionLength == 0 )
                OnCursorPositionChanged( e );
            else
                base.OnSelectionChanged( e );
        }

        public int CurrentColumn
        {
            get { return CursorPosition.Column( this, SelectionStart ); }
        }

        public int CurrentLine
        {
            get { return CursorPosition.Line( this, SelectionStart ); }
        }

        public int CurrentPosition
        {
            get { return this.SelectionStart; }
        }

        public int SelectionEnd
        {
            get { return SelectionStart + SelectionLength; }
        }
    }

    internal class CursorPosition
    {
        [System.Runtime.InteropServices.DllImport("user32")] 
        public static extern int GetCaretPos(ref Point lpPoint);

        private static int GetCorrection(RichTextBox e, int index)
        {
            Point pt1 = Point.Empty;
            GetCaretPos(ref pt1);
            Point pt2 = e.GetPositionFromCharIndex(index);

            if ( pt1 != pt2 )
                return 1;
            else
                return 0;
        }

        public static int Line( RichTextBox e, int index )
        {
             int correction = GetCorrection( e, index );
             return e.GetLineFromCharIndex( index ) - correction + 1;
        }

        public static int Column( RichTextBox e, int index1 )
        {
             int correction = GetCorrection( e, index1 );
             Point p = e.GetPositionFromCharIndex( index1 - correction );

             if ( p.X == 1 )
                 return 1;

             p.X = 0;
             int index2 = e.GetCharIndexFromPosition( p );

             int col = index1 - index2 + 1;

             return col;
         }
    }
}

回答5:

Instead of trying to battle with the default rich text box, why don't you try making your own control so you have full control of the text formatting?

After all, if you're developing your own text editor, it would make sense to have text stored and managed in a way that makes sense to you, the developer, instead of trying to fight with a format designed for a slightly different purpose.

来源：https://stackoverflow.com/questions/17520642/richtextbox-lines-count