Make portion of a Label's Text to be styled bold

Question

Is there any way to make a part of a label.text to be bold?

label.text = \"asd\" + string;

Would like the string

Answer 1

In ASP.NET you could do:

label.Text = string.Format("asd <span style='font-weight: bold;'>{0}</span>", string);

But like everyone else says, depends on what you're using.

Answer 2

The following class illustrates how to do it by overriding OnPaint() in the Label class of WinForms. You can refine it. But what I did was to use the pipe character (|) in a string to tell the OnPaint() method to print text before the | as bold and after it as normal text.

class LabelX : Label
{
    protected override void OnPaint(PaintEventArgs e) {
        Point drawPoint = new Point(0, 0);

        string[] ary = Text.Split(new char[] { '|' });
        if (ary.Length == 2) {
            Font normalFont = this.Font;

            Font boldFont = new Font(normalFont, FontStyle.Bold);

            Size boldSize = TextRenderer.MeasureText(ary[0], boldFont);
            Size normalSize = TextRenderer.MeasureText(ary[1], normalFont);

            Rectangle boldRect = new Rectangle(drawPoint, boldSize);
            Rectangle normalRect = new Rectangle(
                boldRect.Right, boldRect.Top, normalSize.Width, normalSize.Height);

            TextRenderer.DrawText(e.Graphics, ary[0], boldFont, boldRect, ForeColor);
            TextRenderer.DrawText(e.Graphics, ary[1], normalFont, normalRect, ForeColor);
        }
        else {

            TextRenderer.DrawText(e.Graphics, Text, Font, drawPoint, ForeColor);                
        }
    }
}

Here's how to use it:

LabelX x = new LabelX();
Controls.Add(x);
x.Dock = DockStyle.Top;
x.Text = "Hello | World";       

Hello will be printed in bold and world in normal.

Answer 3

This is an elaboration on Simon's suggestion of replacing the Label control with a readonly RichTextBox control.

1. Replace the Label control with a RichTextBox control, same location and size. In following notes the name of the control is rtbResults.

2. Make it readonly: rtbResults.ReadOnly = True;

3. No borders: rtbResults.BorderStyle = BorderStyle.None;

4. Instead of assigning the string to be displayed to Label.Text you assign it to RichTextBox.Rtf, and apply some simple RTF formatting.

The following code is a sample - it displays words generated by a Scrabble cheater program where the high-value letters are in bold.

  /// <summary>
  /// Method to display the results in the RichTextBox, prefixed with "Results: " and with the 
  /// letters J, Q, X and Z in bold type.
  /// </summary>
  private void DisplayResults(string resultString)
  {
     resultString = MakeSubStringBold(resultString, "J");
     resultString = MakeSubStringBold(resultString, "Q");
     resultString = MakeSubStringBold(resultString, "X");
     resultString = MakeSubStringBold(resultString, "Z");

     rtbResults.Rtf = @"{\rtf1\ansi " + "Results: " + resultString + "}";
  }


  /// <summary>
  /// Method to apply RTF-style formatting to make all occurrences of a substring in a string 
  /// bold. 
  /// </summary>
  private static string MakeSubStringBold(string theString, string subString)
  {
     return theString.Replace(subString, @"\b " + subString + @"\b0 ");
  }

Answer 4

Use Infragistics' UltraLabel control - it supports html formatting. There are probably other third party solutions too.

Answer 5

I've built a UserControl that holds a TransparentRichTextBox allowing you to format portions of text by using the RTF syntax.

Nothing special and the syntax is quite easy to understand. Check it out here.

Answer 6

WinForms doesn't allow you to do that.