指定全部显示不同颜色：

public void SetTextContent(string text, ColorEnum color)        {            Font font = new Font("微软雅黑", 14, FontStyle.Bold);            richTextBox1.Font = font;            richTextBox1.Text = text;            richTextBox1.ReadOnly = true;            layoutControlItem2.Selected = true;            SendKeys.Send("{Tab}");  //向活动应用程序发送击键 注意格式：Send("{Tab}");中的{}            switch (color)            {                case ColorEnum.Blue:                    this.Text = "警告信息";                    richTextBox1.ForeColor = Color.Blue;                    break;                case ColorEnum.Red:                    this.Text = "错误信息";                    richTextBox1.ForeColor = Color.Red;                    break;                default:                    this.Text = "提示信息";                    richTextBox1.ForeColor = Color.Black;                    break;            }        }

public enum ColorEnum    {        Black = 0,        Blue = 1,        Red = 2    }

 

指定内容中指定文字高亮显示：

private void SetHighlightContent(string text)        {            ColorEnum color = ColorEnum.Black;            string content = string.Empty;            List
     
       findList = new List
      
       ();            if (text.IndexOf("#Red#", StringComparison.Ordinal) > 0)            {                color = ColorEnum.Red;                var contentArray = text.Split(new[] { "#Red#" }, StringSplitOptions.None);                content = contentArray[0];                var findstrs = contentArray[1];                findList = GetFindList(findstrs);            }            else if (text.IndexOf("#Blue#", StringComparison.Ordinal) > 0)            {                color = ColorEnum.Blue;                var contentArray = text.Split(new[] { "#Blue#" }, StringSplitOptions.None);                content = contentArray[0];                var findstrs = contentArray[1];                findList = GetFindList(findstrs);            }            SetHighlight(content, findList, color);        }        /// 
       
        /// 多个要高亮关键词显示的用'&'连接        /// 
        /// 
               /// 
               private List
       
         GetFindList(string findstrs)        {            List
        
          findList;            if (findstrs.IndexOf("&", StringComparison.Ordinal) > 0)            {                findList = findstrs.Split('&').ToList();            }            else            {                findList = new List
         
          () { findstrs };            }            return findList;        }        private void SetHighlight(string content, List
          
            findList, ColorEnum color) { if (!string.IsNullOrEmpty(content)) { if (findList.IsHasRow()) { Font font = new Font("微软雅黑", 14, FontStyle.Bold); richTextBox1.Font = font; richTextBox1.Text = content; this.Text = @"提示信息"; richTextBox1.ReadOnly = true; foreach (var findItem in findList) { List
           
             findStrIndexes = GetFindStrIndexes(content, findItem); foreach (var itemindex in findStrIndexes) { richTextBox1.Select(itemindex, findItem.Length); switch (color) { case ColorEnum.Blue: richTextBox1.SelectionColor = Color.Blue; break; case ColorEnum.Red: richTextBox1.SelectionColor = Color.Red; break; } } } richTextBox1.SelectionStart = richTextBox1.Text.Length; //取消选中 layoutControlItem2.Selected = true; SendKeys.Send("{Tab}"); //向活动应用程序发送击键 注意格式：Send("{Tab}");中的{} } else { SetTextContent(content, color); } } } private List
            
              GetFindStrIndexes(string content, string findStr) { List
             
               result = new List
              
               (); int start = 0; while (start < content.Length) { int index = content.IndexOf(findStr, start, StringComparison.Ordinal); if (index >= 0) { result.Add(index); start = index + findStr.Length; } else { break; } } return result; }
              
             
            
           
          
         
        
       
      
     

参考：

http://www.cnblogs.com/KardelXiao/p/4236045.html （C#）RichTextBox控件 链接跳转设置

http://blog.csdn.net/crazytaliban/article/details/52002657 RichTextBox用法——设置指定字符串的颜色