Color different parts of a RichTextBox string

Question

I m trying to color parts of a string to be appended to a RichTextBox  I have a string built from different strings   string temp         DateTime Now ToShortTimeString                          userid         message   Environment NewLine    This is what the message would look like once it is constructed       9 23pm  User  my message here    I want everything within and including the brackets  9 23  to be one color   user  to be another color and the message to be another color  Then I d like the string appended to my RichTextBox   How can I accomplish this

User · Answer

This is the modified version that I put in my code (I'm using .Net 4.5) but I think it should work on 4.0 too.

public void AppendText(string text, Color color, bool addNewLine = false)
{
        box.SuspendLayout();
        box.SelectionColor = color;
        box.AppendText(addNewLine
            ? $"{text}{Environment.NewLine}"
            : text);
        box.ScrollToCaret();
        box.ResumeLayout();
}

Differences with original one:

possibility to add text to a new line or simply append it
no need to change selection, it works the same
inserted ScrollToCaret to force autoscroll
added suspend/resume layout calls

User · Answer

I created this Function after researching on the internet since I wanted to print an XML string when you select a row from a data grid view  static void HighlightPhrase RichTextBox box  string StartTag  string EndTag  string ControlTag  Color color1  Color color2        int pos   box SelectionStart      string s   box Text      for  int ix   0                    int jx   s IndexOf StartTag  ix  StringComparison CurrentCultureIgnoreCase           if  jx  lt  0  break          int ex   s IndexOf EndTag  ix  StringComparison CurrentCultureIgnoreCase           box SelectionStart   jx          box SelectionLength   ex - jx   1          box SelectionColor   color1                   int bx   s IndexOf ControlTag  ix  StringComparison CurrentCultureIgnoreCase           int bxtest   s IndexOf StartTag   ex   1   StringComparison CurrentCultureIgnoreCase           if  bx    bxtest                        box SelectionStart   ex   1              box SelectionLength   bx - ex   1              box SelectionColor   color2                             ix   ex   1            box SelectionStart   pos      box SelectionLength   0     and this is how you call it    HighlightPhrase richTextBox1   quot  lt  quot    quot  gt  quot   quot  lt   quot   Color Red  Color Black

User · Answer

private void Log string s   Color  c   null                        richTextBox SelectionStart   richTextBox TextLength              richTextBox SelectionLength   0              richTextBox SelectionColor   c    Color Black              richTextBox AppendText  richTextBox Lines Count      0        Environment NewLine    DateTime Now     t    s               richTextBox SelectionColor   Color Black

User · Answer

I have expanded the method with font as a parameter   public static void AppendText this RichTextBox box  string text  Color color  Font font        box SelectionStart   box TextLength      box SelectionLength   0       box SelectionColor   color      box SelectionFont   font      box AppendText text       box SelectionColor   box ForeColor

User · Answer

Selecting text as said from somebody  may the selection appear momentarily  In Windows Forms applications there is no other solutions for the problem  but today I found a bad  working  way to solve  you can put a PictureBox in overlapping to the RichtextBox with the screenshot of if  during the selection and the changing color or font  making it after reappear all  when the operation is complete   Code is here       The PictureBox has to be invisible before this  at creation   tb variable is your RichTextBox   inputPreview variable is your PictureBox using  Graphics g   inputPreview CreateGraphics          Point loc   tb PointToScreen new Point 0  0        g CopyFromScreen loc  loc  tb Size       Point pt   tb GetPositionFromCharIndex tb TextLength       g FillRectangle new SolidBrush Color Red   new Rectangle pt X  0  100  tb Height      inputPreview Invalidate    inputPreview Show      Your code here  example  tb Select       tb SelectionColor         inputPreview Hide      Better is to use WPF  this solution isn t perfect  but for Winform it works

User · Answer

It s work for me  I hope it will be useful to you   public static RichTextBox RichTextBoxChangeWordColor ref RichTextBox rtb  string startWord  string endWord  Color color        rtb SuspendLayout        Point scroll   rtb AutoScrollOffset      int slct   rtb SelectionIndent      int ss   rtb SelectionStart      List lt Point gt  ls   GetAllWordsIndecesBetween rtb Text  startWord  endWord  true       foreach  var item in ls                rtb SelectionStart   item X          rtb SelectionLength   item Y - item X          rtb SelectionColor   color            rtb SelectionStart   ss      rtb SelectionIndent   slct      rtb AutoScrollOffset   scroll      rtb ResumeLayout true       return rtb     public static List lt Point gt  GetAllWordsIndecesBetween string intoText  string fromThis  string toThis bool withSigns   true        List lt Point gt  result   new List lt Point gt         Stack lt int gt  stack   new Stack lt int gt         bool start   false      for  int i   0  i  lt  intoText Length  i                  string ssubstr   intoText Substring i           if  ssubstr StartsWith fromThis   amp  amp    fromThis    toThis  amp  amp   start      ssubstr StartsWith toThis                          if   withSigns  i    fromThis Length              start   true              stack Push i                     else if  ssubstr StartsWith toThis                          if  withSigns  i    toThis Length              start   false              if  stack Count  gt  0                                int startindex   stack Pop                    result Add new Point startindex i                                      return result

User · Answer

Here is an extension method that overloads the AppendText method with a color parameter   public static class RichTextBoxExtensions       public static void AppendText this RichTextBox box  string text  Color color                box SelectionStart   box TextLength          box SelectionLength   0           box SelectionColor   color          box AppendText text           box SelectionColor   box ForeColor            And this is how you would use it   var userid    USER0001   var message    Access denied   var box   new RichTextBox                                   Dock   DockStyle Fill                    Font   new Font  Courier New   10                    box AppendText       DateTime Now ToShortTimeString          Color Red   box AppendText       box AppendText userid  Color Green   box AppendText        box AppendText message  Color Blue   box AppendText Environment NewLine    new Form  Controls    box   ShowDialog      Note that you may notice some flickering if you re outputting a lot of messages  See this C  Corner article for ideas on how to reduce RichTextBox flicker

User · Answer

Using Selection in WPF  aggregating from several other answers  no other code is required  except Severity enum and GetSeverityColor function    public void Log string msg  Severity severity   Severity Info                string ts         DateTime Now ToString  HH mm ss                   string msg2   ts   msg     n           richTextBox AppendText msg2            if  severity  gt  Severity Info                        int nlcount   msg2 ToCharArray   Count a   gt  a      n                int len   msg2 Length   3    nlcount  2    newlines are longer  this formula works fine             TextPointer myTextPointer1   richTextBox Document ContentEnd GetPositionAtOffset -len               TextPointer myTextPointer2   richTextBox Document ContentEnd GetPositionAtOffset -1                richTextBox Selection Select myTextPointer1 myTextPointer2               SolidColorBrush scb   new SolidColorBrush GetSeverityColor severity                richTextBox Selection ApplyPropertyValue TextElement BackgroundProperty  scb                       richTextBox ScrollToEnd

User · Answer

I think modifying a  selected text  in a RichTextBox isn t the right way to add colored text  So here a method to add a  color block             Run run   new Run  This is my text            run Foreground   new SolidColorBrush Colors Red      My Color         Paragraph paragraph   new Paragraph run           MyRichTextBlock Document Blocks Add paragraph     From MSDN       The Blocks property is the content property of RichTextBox  It is a   collection of Paragraph elements  Content in each Paragraph element   can contain the following elements           Inline   InlineUIContainer   Run   Span   Bold   Hyperlink   Italic   Underline   LineBreak      So I think you have to split your string depending on parts color  and create as many Run objects as needed

[c#] Color different parts of a RichTextBox string

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