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.ToSh         


        

Answer 1

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 > Severity.Info)
        {
            int nlcount = msg2.ToCharArray().Count(a => 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();
    }