Formatting text in WinForm Label

Question

Is it possible to format certain text in a WinForm Label instead of breaking the text into multiple labels? Please disregard the HTML tags within the label's text; it's only used to get my point out.

For example:

Dim myLabel As New Label
myLabel.Text = "This is <b>bold</b> text.  This is <i>italicized</i> text."

Which would produce the text in the label as:

This is bold text. This is italicized text.

Answer 1

Worked solution for me - using custom RichEditBox. With right properties it will be looked as simple label with bold support.

1) First, add your custom RichTextLabel class with disabled caret :

public class RichTextLabel : RichTextBox
{
    public RichTextLabel()
    {
        base.ReadOnly = true;
        base.BorderStyle = BorderStyle.None;
        base.TabStop = false;
        base.SetStyle(ControlStyles.Selectable, false);
        base.SetStyle(ControlStyles.UserMouse, true);
        base.SetStyle(ControlStyles.SupportsTransparentBackColor, true);

        base.MouseEnter += delegate(object sender, EventArgs e)
        {
            this.Cursor = Cursors.Default;
        };
    }

    protected override void WndProc(ref Message m)
    {
        if (m.Msg == 0x204) return; // WM_RBUTTONDOWN
        if (m.Msg == 0x205) return; // WM_RBUTTONUP
        base.WndProc(ref m);
    }
}

2) Split you sentence to words with IsSelected flag, that determine if that word should be bold or no :

        private void AutocompleteItemControl_Load(object sender, EventArgs e)
    {
        RichTextLabel rtl = new RichTextLabel();
        rtl.Font = new Font("MS Reference Sans Serif", 15.57F);
        StringBuilder sb = new StringBuilder();
        sb.Append(@"{\rtf1\ansi ");
        foreach (var wordPart in wordParts)
        {
            if (wordPart.IsSelected)
            {
                sb.Append(@"\b ");
            }
            sb.Append(ConvertString2RTF(wordPart.WordPart));
            if (wordPart.IsSelected)
            {
                sb.Append(@"\b0 ");
            }
        }
        sb.Append(@"}");

        rtl.Rtf = sb.ToString();
        rtl.Width = this.Width;
        this.Controls.Add(rtl);
    }

3) Add function for convert you text to valid rtf (with unicode support!) :

   private string ConvertString2RTF(string input)
    {
        //first take care of special RTF chars
        StringBuilder backslashed = new StringBuilder(input);
        backslashed.Replace(@"\", @"\\");
        backslashed.Replace(@"{", @"\{");
        backslashed.Replace(@"}", @"\}");

        //then convert the string char by char
        StringBuilder sb = new StringBuilder();
        foreach (char character in backslashed.ToString())
        {
            if (character <= 0x7f)
                sb.Append(character);
            else
                sb.Append("\\u" + Convert.ToUInt32(character) + "?");
        }
        return sb.ToString();
    }

Works like a charm for me! Solutions compiled from :

How to convert a string to RTF in C#?

Format text in Rich Text Box

How to hide the caret in a RichTextBox?

Answer 2

1. Create the text as a RTF file in wordpad
2. Create Rich text control with no borders and editable = false
3. Add the RTF file to the project as a resource

4. In the Form1_load do

   myRtfControl.Rtf = Resource1.MyRtfControlText

Answer 3

AutoRichLabel

      

I was solving this problem by building an UserControl that contains a TransparentRichTextBox that is readonly. The TransparentRichTextBox is a RichTextBox that allows to be transparent:

TransparentRichTextBox.cs:

public class TransparentRichTextBox : RichTextBox
{
    [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
    static extern IntPtr LoadLibrary(string lpFileName);

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams prams = base.CreateParams;
            if (TransparentRichTextBox.LoadLibrary("msftedit.dll") != IntPtr.Zero)
            {
                prams.ExStyle |= 0x020; // transparent 
                prams.ClassName = "RICHEDIT50W";
            }
            return prams;
        }
    }
}

The final UserControl acts as wrapper of the TransparentRichTextBox. Unfortunately, I had to limit it to AutoSize on my own way, because the AutoSize of the RichTextBox became broken.

AutoRichLabel.designer.cs:

partial class AutoRichLabel
{
    /// <summary> 
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary> 
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Component Designer generated code

    /// <summary> 
    /// Required method for Designer support - do not modify 
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.rtb = new TransparentRichTextBox();
        this.SuspendLayout();
        // 
        // rtb
        // 
        this.rtb.BorderStyle = System.Windows.Forms.BorderStyle.None;
        this.rtb.Dock = System.Windows.Forms.DockStyle.Fill;
        this.rtb.Location = new System.Drawing.Point(0, 0);
        this.rtb.Margin = new System.Windows.Forms.Padding(0);
        this.rtb.Name = "rtb";
        this.rtb.ReadOnly = true;
        this.rtb.ScrollBars = System.Windows.Forms.RichTextBoxScrollBars.None;
        this.rtb.Size = new System.Drawing.Size(46, 30);
        this.rtb.TabIndex = 0;
        this.rtb.Text = "";
        this.rtb.WordWrap = false;
        this.rtb.ContentsResized += new System.Windows.Forms.ContentsResizedEventHandler(this.rtb_ContentsResized);
        // 
        // AutoRichLabel
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;
        this.BackColor = System.Drawing.Color.Transparent;
        this.Controls.Add(this.rtb);
        this.Name = "AutoRichLabel";
        this.Size = new System.Drawing.Size(46, 30);
        this.ResumeLayout(false);

    }

    #endregion

    private TransparentRichTextBox rtb;
}

AutoRichLabel.cs:

/// <summary>
/// <para>An auto sized label with the ability to display text with formattings by using the Rich Text Format.</para>
/// <para>­</para>
/// <para>Short RTF syntax examples: </para>
/// <para>­</para>
/// <para>Paragraph: </para>
/// <para>{\pard This is a paragraph!\par}</para>
/// <para>­</para>
/// <para>Bold / Italic / Underline: </para>
/// <para>\b bold text\b0</para>
/// <para>\i italic text\i0</para>
/// <para>\ul underline text\ul0</para>
/// <para>­</para>
/// <para>Alternate color using color table: </para>
/// <para>{\colortbl ;\red0\green77\blue187;}{\pard The word \cf1 fish\cf0  is blue.\par</para>
/// <para>­</para>
/// <para>Additional information: </para>
/// <para>Always wrap every text in a paragraph. </para>
/// <para>Different tags can be stacked (i.e. \pard\b\i Bold and Italic\i0\b0\par)</para>
/// <para>The space behind a tag is ignored. So if you need a space behind it, insert two spaces (i.e. \pard The word \bBOLD\0  is bold.\par)</para>
/// <para>Full specification: http://www.biblioscape.com/rtf15_spec.htm </para>
/// </summary>
public partial class AutoRichLabel : UserControl
{
    /// <summary>
    /// The rich text content. 
    /// <para>­</para>
    /// <para>Short RTF syntax examples: </para>
    /// <para>­</para>
    /// <para>Paragraph: </para>
    /// <para>{\pard This is a paragraph!\par}</para>
    /// <para>­</para>
    /// <para>Bold / Italic / Underline: </para>
    /// <para>\b bold text\b0</para>
    /// <para>\i italic text\i0</para>
    /// <para>\ul underline text\ul0</para>
    /// <para>­</para>
    /// <para>Alternate color using color table: </para>
    /// <para>{\colortbl ;\red0\green77\blue187;}{\pard The word \cf1 fish\cf0  is blue.\par</para>
    /// <para>­</para>
    /// <para>Additional information: </para>
    /// <para>Always wrap every text in a paragraph. </para>
    /// <para>Different tags can be stacked (i.e. \pard\b\i Bold and Italic\i0\b0\par)</para>
    /// <para>The space behind a tag is ignored. So if you need a space behind it, insert two spaces (i.e. \pard The word \bBOLD\0  is bold.\par)</para>
    /// <para>Full specification: http://www.biblioscape.com/rtf15_spec.htm </para>
    /// </summary>
    [Browsable(true)]
    public string RtfContent
    {
        get
        {
            return this.rtb.Rtf;
        }
        set
        {
            this.rtb.WordWrap = false; // to prevent any display bugs, word wrap must be off while changing the rich text content. 
            this.rtb.Rtf = value.StartsWith(@"{\rtf1") ? value : @"{\rtf1" + value + "}"; // Setting the rich text content will trigger the ContentsResized event. 
            this.Fit(); // Override width and height. 
            this.rtb.WordWrap = this.WordWrap; // Set the word wrap back. 
        }
    }

    /// <summary>
    /// Dynamic width of the control. 
    /// </summary>
    [Browsable(false)]
    public new int Width
    {
        get
        {
            return base.Width;
        } 
    }

    /// <summary>
    /// Dynamic height of the control. 
    /// </summary>
    [Browsable(false)]
    public new int Height
    {
        get
        {
            return base.Height;
        }
    }

    /// <summary>
    /// The measured width based on the content. 
    /// </summary>
    public int DesiredWidth { get; private set; }

    /// <summary>
    /// The measured height based on the content. 
    /// </summary>
    public int DesiredHeight { get; private set; }

    /// <summary>
    /// Determines the text will be word wrapped. This is true, when the maximum size has been set. 
    /// </summary>
    public bool WordWrap { get; private set; }

    /// <summary>
    /// Constructor. 
    /// </summary>
    public AutoRichLabel()
    {
        InitializeComponent();
    }

    /// <summary>
    /// Overrides the width and height with the measured width and height
    /// </summary>
    public void Fit()
    {
        base.Width = this.DesiredWidth;
        base.Height = this.DesiredHeight;
    }

    /// <summary>
    /// Will be called when the rich text content of the control changes. 
    /// </summary>
    private void rtb_ContentsResized(object sender, ContentsResizedEventArgs e)
    {
        this.AutoSize = false; // Disable auto size, else it will break everything
        this.WordWrap = this.MaximumSize.Width > 0; // Enable word wrap when the maximum width has been set. 
        this.DesiredWidth = this.rtb.WordWrap ? this.MaximumSize.Width : e.NewRectangle.Width; // Measure width. 
        this.DesiredHeight = this.MaximumSize.Height > 0 && this.MaximumSize.Height < e.NewRectangle.Height ? this.MaximumSize.Height : e.NewRectangle.Height; // Measure height. 
        this.Fit(); // Override width and height. 
    }
}

The syntax of the rich text format is quite simple:

Paragraph:

{\pard This is a paragraph!\par}

Bold / Italic / Underline text:

\b bold text\b0
\i italic text\i0
\ul underline text\ul0

Alternate color using color table:

{\colortbl ;\red0\green77\blue187;}
{\pard The word \cf1 fish\cf0  is blue.\par

But please note: Always wrap every text in a paragraph. Also, different tags can be stacked (i.e. \pard\b\i Bold and Italic\i0\b0\par) and the space character behind a tag is ignored. So if you need a space behind it, insert two spaces (i.e. \pard The word \bBOLD\0 is bold.\par). To escape \ or { or }, please use a leading \. For more information there is a full specification of the rich text format online.

Using this quite simple syntax you can produce something like you can see in the first image. The rich text content that was attached to the RtfContent property of my AutoRichLabel in the first image was:

{\colortbl ;\red0\green77\blue187;}
{\pard\b BOLD\b0  \i ITALIC\i0  \ul UNDERLINE\ul0 \\\{\}\par}
{\pard\cf1\b BOLD\b0  \i ITALIC\i0  \ul UNDERLINE\ul0\cf0 \\\{\}\par}

If you want to enable word wrap, please set the maximum width to a desired size. However, this will fix the width to the maximum width, even when the text is shorter.

Have fun!

Answer 4

Not really, but you could fake it with a read-only RichTextBox without borders. RichTextBox supports Rich Text Format (rtf).

Answer 5

Another workaround, late to the party: if you don't want to use a third party control, and you're just looking to call attention to some of the text in your label, and you're ok with underlines, you can use a LinkLabel.

Note that many consider this a 'usability crime', but if you're not designing something for end user consumption then it may be something you're prepared to have on your conscience.

The trick is to add disabled links to the parts of your text that you want underlined, and then globally set the link colors to match the rest of the label. You can set almost all the necessary properties at design-time apart from the Links.Add() piece, but here they are in code:

linkLabel1.Text = "You are accessing a government system, and all activity " +
                  "will be logged.  If you do not wish to continue, log out now.";
linkLabel1.AutoSize = false;
linkLabel1.Size = new Size(365, 50);
linkLabel1.TextAlign = ContentAlignment.MiddleCenter;
linkLabel1.Links.Clear();
linkLabel1.Links.Add(20, 17).Enabled = false;   // "government system"
linkLabel1.Links.Add(105, 11).Enabled = false;  // "log out now"
linkLabel1.LinkColor = linkLabel1.ForeColor;
linkLabel1.DisabledLinkColor = linkLabel1.ForeColor;

Result:

Answer 6

A FlowLayoutPanel works well for your problem. If you add labels to the flow panel and format each label's font and margin properties, then you can have different font styles. Pretty quick and easy solution to get working.