I have a RichTextBox full of text from a text file I want now to color in red all the places the word "Error" is in the text how to do it?

I tried to do it in the backgroundworker_ProgressChanged event but its coloring in red some areas in the text and I didn't see in those areas the word "Error".

What am I doing wrong ?

This the part of the code where I'm trying to color the word "Error" in any place in the text. What I want is to paint each place in the text that there is a word "Error" and only the word "Error" and after I want to paint the whole line where the word "Error" is exist in it.

void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
      this.progressBar1.Value = e.ProgressPercentage;
      this.richTextBox1.AppendText(e.UserState.ToString());
        if (e.UserState.ToString().Contains("Error"))
        {
            Invoke(new Action(() => richTextBox1.SelectionColor = Color.Red));
        }
    }

And this is the complete code of the new form:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Threading;

namespace WindowsFormsApplication1
{
    public partial class textBoxLoggerViewer : Form
    {
        //all the text-lines
    string[] allText;
开发者_StackOverflow社区    //counter
    int lineCounter = 0;
    //amount of lines to display
    private int maxDisplayAmount = 2000;

    string log_file_name = @"\logger.txt";
    string logger_file_to_read = Path.GetDirectoryName(Application.LocalUserAppDataPath) + @"\log";

    //string logger_file_to_read = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory);
    BackgroundWorker bgw = null;

    public textBoxLoggerViewer()
    {
      InitializeComponent();
      label1.Text = "Loading text please wait";
      richTextBox1.Font = new Font("Consolas", 8f, FontStyle.Bold);
      richTextBox1.BackColor = Color.AliceBlue;
      richTextBox1.SelectionColor = Color.Black;
      richTextBox1.DoubleClick += new EventHandler(richTextBox1_DoubleClick);
      richTextBox1.Enabled = false;

      this.Shown += new EventHandler(textBoxLoggerViewer_Shown);

      bgw = new BackgroundWorker();
      bgw.WorkerReportsProgress = true;
      bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
      bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
      bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);

      this.FormClosed += new FormClosedEventHandler(textBoxLoggerViewer_FormClosed);
    }

    void textBoxLoggerViewer_FormClosed(object sender, FormClosedEventArgs e)
    {
      this.bgw.Dispose();
    }

    void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
      this.progressBar1.Value = e.ProgressPercentage;
      this.richTextBox1.AppendText(e.UserState.ToString());
        if (e.UserState.ToString().Contains("Error"))
        {
            Invoke(new Action(() => richTextBox1.SelectionColor = Color.Red));
        }
    }

    void bgw_DoWork(object sender, DoWorkEventArgs e)
    {
      this.allText = File.ReadAllLines(logger_file_to_read + log_file_name);
      while (lineCounter < allText.Length - 1)
      {
        string current = ReadText();
        //get current amount in percent
        bgw.ReportProgress((int)(((double)this.lineCounter / (double)allText.Length) * 100), current);
      }
    }

    void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
      this.richTextBox1.Enabled = true;
      progressBar1.Enabled = false;
      progressBar1.Visible = false;
      label1.Text = "All the text have been loaded successfully";
    }

    void textBoxLoggerViewer_Shown(object sender, EventArgs e)
    {
      bgw.RunWorkerAsync();
    }

    void richTextBox1_DoubleClick(object sender, EventArgs e)
    {
      ReadText();
    }

    //will be called from bgw
    private string ReadText()
    {
      StringBuilder sb = new StringBuilder();

      int curLine = lineCounter;
      for (int i = curLine; i < Math.Min(curLine + maxDisplayAmount, allText.Length); i++)
      {
        sb.Append(i.ToString() + "\t\t" + allText[i] + "\r\n");
        lineCounter++;
      /*  if (allText[i].Contains("Error"))
        {
            Invoke(new Action(() => richTextBox1.SelectionColor = Color.Red));
        }*/
      }
      return sb.ToString();
    }
  }
}

BTW: I wanted to add to the progressbar "%" with numbers so when the progressbar is in progress it will count percentages and show them now its just showing this green bar I want in the front of the green bar to show the percentages. like %1 %2 %3 or 1% 2% 3% or without the "%" I don't know how to do it tried many ways didn't work.

Thanks.

You need to select the word Error in the string before you set the selection color:

RichTextBox1.SelectionStart = [redStringStart]
RichTextBox1.SelectionLength = [redStringLength]
RichTextBox1.SelectionColor = Color.Red