Change color and font for some part of text in WPF C#

Question

Is there a way to change color and font for some part of text which I want to put on TextBox or RichTextBox. I am using C# WPF.

For example

 richTextBox.AppendText("Text1 " + word + " Text2 ");

Variable word for example to be other color and font from Text1 and Text2. Is it possible and how to do this?

Answer 1

If you just want to do some quick coloring, the simplest solution may be to use the end of the RTB content as a Range and apply formatting to it. For example:

TextRange rangeOfText1 = new TextRange(richTextBox.Document.ContentEnd, richTextBox.Document.ContentEnd);
rangeOfText1.Text = "Text1 ";
rangeOfText1.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Blue);
rangeOfText1.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold);

TextRange rangeOfWord = new TextRange(richTextBox.Document.ContentEnd, richTextBox.Document.ContentEnd);
rangeOfWord.Text = "word ";
rangeOfWord.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Red);
rangeOfWord.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Regular);

TextRange rangeOfText2 = new TextRange(richTextBox.Document.ContentEnd, richTextBox.Document.ContentEnd);
rangeOfText2.Text = "Text2 ";
rangeOfText2.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Blue);
rangeOfText2.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold);

If you are looking for a more advanced solution, I suggest reading this Microsoft Doc about Flow Document , as it gives you a great flexibility in formatting your text.

Answer 2

You can try this out.

public TestWindow()
{
    InitializeComponent();

    this.paragraph = new Paragraph();
    rich1.Document = new FlowDocument(paragraph);

    var from = "user1";
    var text = "chat message goes here";
    paragraph.Inlines.Add(new Bold(new Run(from + ": "))
    {
        Foreground = Brushes.Red
    });
    paragraph.Inlines.Add(text);
    paragraph.Inlines.Add(new LineBreak());
    this.DataContext = this;
}
private Paragraph paragraph;

Use the Document property of the RichTextBox.

Answer 3

I have made my own class to manipulate Text s of TextBlock , TextBox ...

/// <summary>
/// Class for text manipulation operations
/// </summary>
public class TextManipulation
{
    /// <summary>
    /// Is manipulating a specific string inside of a TextPointer Range (TextBlock, TextBox...)
    /// </summary>
    /// <param name="startPointer">Starting point where to look</param>
    /// <param name="endPointer">Endpoint where to look</param>
    /// <param name="keyword">This is the string you want to manipulate</param>
    /// <param name="fontStyle">The new FontStyle</param>
    /// <param name="fontWeight">The new FontWeight</param>
    /// <param name="foreground">The new foreground</param>
    /// <param name="background">The new background</param>
    /// <param name="fontSize">The new FontSize</param>
    public static void FromTextPointer(TextPointer startPointer, TextPointer endPointer, string keyword, FontStyle fontStyle, FontWeight fontWeight, Brush foreground, Brush background, double fontSize)
    {
        FromTextPointer(startPointer, endPointer, keyword, fontStyle, fontWeight, foreground, background, fontSize, null);
    }

    /// <summary>
    /// Is manipulating a specific string inside of a TextPointer Range (TextBlock, TextBox...)
    /// </summary>
    /// <param name="startPointer">Starting point where to look</param>
    /// <param name="endPointer">Endpoint where to look</param>
    /// <param name="keyword">This is the string you want to manipulate</param>
    /// <param name="fontStyle">The new FontStyle</param>
    /// <param name="fontWeight">The new FontWeight</param>
    /// <param name="foreground">The new foreground</param>
    /// <param name="background">The new background</param>
    /// <param name="fontSize">The new FontSize</param>
    /// <param name="newString">The New String (if you want to replace, can be null)</param>
    public static void FromTextPointer(TextPointer startPointer, TextPointer endPointer, string keyword, FontStyle fontStyle, FontWeight fontWeight, Brush foreground, Brush background, double fontSize, string newString)
    {
        if(startPointer == null)throw new ArgumentNullException(nameof(startPointer));
        if(endPointer == null)throw new ArgumentNullException(nameof(endPointer));
        if(string.IsNullOrEmpty(keyword))throw new ArgumentNullException(keyword);

        TextRange text = new TextRange(startPointer, endPointer);
        TextPointer current = text.Start.GetInsertionPosition(LogicalDirection.Forward);
        while (current != null)
        {
            string textInRun = current.GetTextInRun(LogicalDirection.Forward);
            if (!string.IsNullOrWhiteSpace(textInRun))
            {
                int index = textInRun.IndexOf(keyword);
                if (index != -1)
                {
                    TextPointer selectionStart = current.GetPositionAtOffset(index,LogicalDirection.Forward);
                    TextPointer selectionEnd = selectionStart.GetPositionAtOffset(keyword.Length,LogicalDirection.Forward);
                    TextRange selection = new TextRange(selectionStart, selectionEnd);

                    if(!string.IsNullOrEmpty(newString))
                        selection.Text = newString;

                    selection.ApplyPropertyValue(TextElement.FontSizeProperty, fontSize);
                    selection.ApplyPropertyValue(TextElement.FontStyleProperty, fontStyle);
                    selection.ApplyPropertyValue(TextElement.FontWeightProperty, fontWeight);
                    selection.ApplyPropertyValue(TextElement.ForegroundProperty, foreground);
                    selection.ApplyPropertyValue(TextElement.BackgroundProperty, background);
                }
            }
            current = current.GetNextContextPosition(LogicalDirection.Forward);
        }
    }
}

Usage

TextManipulation.FromTextPointer(_TextBlock.ContentStart, _TextBlock.ContentEnd, "IWantToBeManipulated", NewFontStyle, NewFontWeight, NewForeground, NewBackground, NewFontSize);
TextManipulation.FromTextPointer(_TextBlock.ContentStart, _TextBlock.ContentEnd, "IWantToBeManipulated", NewFontStyle, NewFontWeight, NewForeground, NewBackground, NewFontSize, "NewStringIfYouWant");

Answer 4

You need to use the Document property of RichTextBox and add a Run to it.

Document property: http://msdn.microsoft.com/en-us/library/system.windows.controls.richtextbox.document.aspx
Run: http://msdn.microsoft.com/en-us/library/system.windows.documents.run.aspx

Answer 5

If you want to first add a line and then color parts of it afterwards, a little change to the answer of @Gimno might help:

TextRange rangeOfLine = new TextRange(rtbTest.Document.ContentEnd, rtbTest.Document.ContentEnd);
rangeOfLine.Text = "This is a long string";
rangeOfLine.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Black);

TextRange rangeToColor = new TextRange(rtbTest.Document.ContentEnd.GetPositionAtOffset(-5), rtbTest.Document.ContentEnd.GetPositionAtOffset(-2));
rangeToColor.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Red);

This lets you add a line of text to the rich text box first, which is colored black. After it was added a selection from -5 to -2 according to the end of the content gets colored red.

My string which I add to the RTB gets appended in multiple functions, so it would be quite unhandy if the coloring had to appear for each snippet in the according function.