Numbered list on Richtextbox

Question

I'm trying to add numbered list functionality to a text editor. RichTextbox already provides the SelectionBullet property to change a selection to a bulleted list. But i was unable to find a similar property to generate numbered list. Is there any standard way to create a numbered list on Richtextbox. If not, i would have to implement it myself so code snips that could help me do that will help, Thank you.

Answer 1

Here is my answer... which is easily readable and refineable. I took a much different approach but added the ability to remove the numbered list within the selection if it already exists. Please note that so far I have only lightly tested it and it seems to work good... but it may need further refinement.

    private void btnOrdered_Click(object sender, EventArgs e)
    {
        string[] splitSelection = null;
        // If selection split selection else split everything
        if (this.txtCaptionEditor.SelectionLength > 0)
        {
            splitSelection = this.txtCaptionEditor.SelectedText.Replace("\r\n", "\n").Split("\n".ToCharArray());
        }
        else
        {
            splitSelection = this.txtCaptionEditor.Text.Replace("\r\n", "\n").Split("\n".ToCharArray());
        }
        bool Exists = false;
        for (int i = 0; i < splitSelection.GetLength(0); i++)
        {
            // If Ordered List Allready exists in selection then remove else add
            if (!string.IsNullOrEmpty(splitSelection[i]))
            {
                if (splitSelection[i].Substring(0, 2) == "1.") { Exists = true; }
            }
        }

        for (int i = 0; i < splitSelection.GetLength(0); i++)
        {
            int lineCount = (i + 1);
            if (Exists)
            {
                this.txtCaptionEditor.Text = this.txtCaptionEditor.Text.Replace(Convert.ToString(lineCount) + ".  ", "");
            }
            else
            {
                if(!string.IsNullOrEmpty(splitSelection[i]))
                {
                    this.txtCaptionEditor.Text = this.txtCaptionEditor.Text.Replace(splitSelection[i], Convert.ToString(lineCount) + ".  " + splitSelection[i]);
                }

            }
        }
    }

    private void txtCaptionEditor_KeyDown(object sender, KeyEventArgs e)
    {
        string[] splitSelection = this.txtCaptionEditor.Text.Replace("\r\n", "\n").Split("\n".ToCharArray());
        if (e.KeyCode == Keys.Enter)
        {
            // Get Current Line Position
            int currentLine = this.txtCaptionEditor.GetLineFromCharIndex(this.txtCaptionEditor.SelectionStart);
            // Only Run if the previous line is greater than zero
            if ((currentLine) >= 0)
            {
                // Loop through 100 possible numbers for match you can go higher 
                // If you think your numbered list could go above 100
                for (int i = 0; i < 100; i++)
                {
                    if (splitSelection[(currentLine)].Substring(0, 2) == Convert.ToString((i + 1)) + ".")
                    {
                        // If the substring of the current line equals a numbered list                value.. enumerate next line
                        this.txtCaptionEditor.SelectedText = "\n" + (i + 2) + ".  ";
                        e.SuppressKeyPress = true;
                    }
                }
            }
        }
    }

Answer 2

Well, i implemented it as follows.

  private void btnNumbers_Click(object sender, EventArgs e)
        {
            string temptext = rtbMain.SelectedText;

            int SelectionStart = rtbMain.SelectionStart;
            int SelectionLength = rtbMain.SelectionLength;

            rtbMain.SelectionStart = rtbMain.GetFirstCharIndexOfCurrentLine();
            rtbMain.SelectionLength = 0;
            rtbMain.SelectedText = "1. ";

            int j = 2;
            for( int i = SelectionStart; i < SelectionStart + SelectionLength; i++)
                if (rtbMain.Text[i] == '\n')
                {
                    rtbMain.SelectionStart = i + 1;
                    rtbMain.SelectionLength = 0;
                    rtbMain.SelectedText = j.ToString() + ". ";
                    j++;
                    SelectionLength += 3;
                }

        }

        private void rtbMain_KeyDown(object sender, KeyEventArgs e)
        {//this piece of code automatically increments the bulleted list when user //presses Enter key
            int tempNum;
            if (e.KeyCode == Keys.Enter)
                try
                    {
                        if (char.IsDigit(rtbMain.Text[rtbMain.GetFirstCharIndexOfCurrentLine()]))
                        {
                            if (char.IsDigit(rtbMain.Text[rtbMain.GetFirstCharIndexOfCurrentLine() + 1]) && rtbMain.Text[rtbMain.GetFirstCharIndexOfCurrentLine() + 2] == '.')
                                tempNum = int.Parse(rtbMain.Text.Substring(rtbMain.GetFirstCharIndexOfCurrentLine(),2));
                            else tempNum = int.Parse(rtbMain.Text[rtbMain.GetFirstCharIndexOfCurrentLine()].ToString());

                            if (rtbMain.Text[rtbMain.GetFirstCharIndexOfCurrentLine() + 1] == '.' || (char.IsDigit(rtbMain.Text[rtbMain.GetFirstCharIndexOfCurrentLine() + 1]) && rtbMain.Text[rtbMain.GetFirstCharIndexOfCurrentLine() + 2] == '.'))
                            {
                                tempNum++;
                                    rtbMain.SelectedText = "\r\n" + tempNum.ToString() + ". ";
                                e.SuppressKeyPress = true;
                            }
                        }  
                    }
                 catch{}
        }

Answer 3

I know that a link is not gernerally accepted as a good answer, however the article RichTextBox with Search Line Numbering, Bulleting, Printing, Searching Support on CodeProject could probably help you out quite a bit with what you are looking for.

In this article, the author extends the RichTextBox control into something that can do what you are asking (and more), plus the code is posted there for all to see.