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Automatically Wrap Text in Label RRS feed

  • Question

  • I have the following scenario: I have a TableLayoutPanel in my form. In one of the cells I want to place a Label control to display some text. The label might have just a few words. It might have a paragraph. I would like the label text to automatically wrap inside the cell in the TableLayoutPanel. If the row in the TLP is not large enough, it should automatically grow so that it can display all of the text.

    1) I have tried setting Dock:Fill and AutoSize:False on the label. This will cause the text in the label to wrap, but it will not grow past the size of the cell in the TLP. If I set the row in the TLP to be AutoSize, the whole row becomes hidden.

    2) If I set it to Dock:Top, AutoSize:False, and set the TLP row to AutoSize, this works, as long as the height of the Label is set to a value sufficient enough to hold all of the text. But if the height is not big enough, the text gets cut off.

    In case 2 above, it seems like I am on the right track, and that it would work if I had some way of dynamically making the Label taller depending on whether it still needed to wrap the text.

    Any suggestions for me on how I can accomplish this?
    Tuesday, November 21, 2006 10:59 PM

Answers

  • Here's a custom label control that automatically adjusts its height.  Add a new class to your project, paste the code shown below and build your project.  You can now drop a GrowLabel control from the top of the toolbox onto your form.

    using System;
    using System.Text;
    using System.Drawing;
    using System.Windows.Forms;

    public class GrowLabel : Label {
      private bool mGrowing;
      public GrowLabel() {
        this.AutoSize = false;
      }
      private void resizeLabel() {
        if (mGrowing) return;
        try {
          mGrowing = true;
          Size sz = new Size(this.Width, Int32.MaxValue);
          sz = TextRenderer.MeasureText(this.Text, this.Font, sz, TextFormatFlags.WordBreak);
          this.Height = sz.Height;
        }
        finally {
          mGrowing = false;
        }
      }
      protected override void OnTextChanged(EventArgs e) {
        base.OnTextChanged(e);
        resizeLabel();
      }
      protected override void OnFontChanged(EventArgs e) {
        base.OnFontChanged(e);
        resizeLabel();
      }
      protected override void OnSizeChanged(EventArgs e) {
        base.OnSizeChanged(e);
        resizeLabel();
      }
    }


    Wednesday, November 22, 2006 2:37 PM
    Moderator

All replies

  • hi,

    FlowLayoutPanel is to be anchored left|right, it has a constraining width, which it passes onto the label.  Setting the FlowLayoutPanel to AutoSize = true, the FlowLayoutPanel will grow in height as the label grows. (The label actually had a constraining width as well when anchored, but for compatibility reasons chose to ignore it.)  Because the label is in a new layout container, it is free to honor the wrapping constraints without the possibility of breaking anyone.  As the dialog is resized, the FlowLayoutPanel is resized, which in-turn passes a new constraint to the label.

    Hope this helps.

    thank you,
    bhanu.

    Wednesday, November 22, 2006 1:24 AM
  • Hi Bhanu,

    Thanks for the help. Unfortunately, it is not working for me yet. Here is what I have:
    • FlowLayoutPanel in a row of the TablePanel (ColSpan:2 to cover both columns)
      • Autosize:True
      • Anchor:left|right
    • Label inside the FLP.
    I have tried every setting that I can think of with the label in terms of docking and anchoring, but I still am unable to get the label to grow in height in order to automatically wrap its text inside the bounds of the FLP. If I set the height large enough to begin with, it will wrap (but it will also be too big when there is only one line of text). If I set the height to fit one line of text, that is all that it shows. Additionally, the width of the label also seems to be set at design time, and will not adhere to the bounds of the FLP at runtime.

    Ultimately, I am looking for the same functionality offered by an HTML table cell: if there is a small amount of text, it will only have one line in the table. As there is more text, the height of the cell will expand as the text wraps. (I thought that this would be easier to do in WinForms...still new at this though)

    Any suggestions would be appreciated.
    Wednesday, November 22, 2006 12:25 PM
  • Here's a custom label control that automatically adjusts its height.  Add a new class to your project, paste the code shown below and build your project.  You can now drop a GrowLabel control from the top of the toolbox onto your form.

    using System;
    using System.Text;
    using System.Drawing;
    using System.Windows.Forms;

    public class GrowLabel : Label {
      private bool mGrowing;
      public GrowLabel() {
        this.AutoSize = false;
      }
      private void resizeLabel() {
        if (mGrowing) return;
        try {
          mGrowing = true;
          Size sz = new Size(this.Width, Int32.MaxValue);
          sz = TextRenderer.MeasureText(this.Text, this.Font, sz, TextFormatFlags.WordBreak);
          this.Height = sz.Height;
        }
        finally {
          mGrowing = false;
        }
      }
      protected override void OnTextChanged(EventArgs e) {
        base.OnTextChanged(e);
        resizeLabel();
      }
      protected override void OnFontChanged(EventArgs e) {
        base.OnFontChanged(e);
        resizeLabel();
      }
      protected override void OnSizeChanged(EventArgs e) {
        base.OnSizeChanged(e);
        resizeLabel();
      }
    }


    Wednesday, November 22, 2006 2:37 PM
    Moderator
  • Thanks, it worked perfectly

    In the meantime, I found the right combination of settings to use to get the regular label to wrap properly:
    • Anchor: Top|Bottom|Left|Right
    • AutoSize: True
    • Dock:None
    What is most interesting about this is that it is wrapping despite AutoSize being true (which is documented as "Note that this is only valid for label controls that do not wrap text"), it is still wrapping!
    Wednesday, November 22, 2006 3:46 PM
  • I'm using the GrowLabel control in the post - but it looks like the last line of the text value is being truncated.

    If I add an arbitrary amount of pixels (i.e. 5) to the height of the label the text is no longer truncated.

    Any ideas on why this is? Any thoughts on a better fix than just simply incrementing the height property of the label until it "works"?

    -Thx


    Monday, July 2, 2007 4:57 PM
  • This may happen if you change the BorderStyle or Padding properties.  Modify the code list this:

      private void resizeLabel() {
        if (mGrowing) return;
        try {
          mGrowing = true;
          Size sz = new Size(this.ClientSize.Width, Int32.MaxValue);
          sz = TextRenderer.MeasureText(this.Text, this.Font, sz, TextFormatFlags.WordBreak);
          this.ClientSize = new Size(this.ClientSize.Width, sz.Height + this.Padding.Vertical);
        }
        finally {
          mGrowing = false;
        }
      }
      protected override void OnPaddingChanged(EventArgs e) {
        base.OnPaddingChanged(e);
        resizeLabel();
      }

    Monday, July 2, 2007 5:13 PM
    Moderator
  • Yup...I should have mentioned that I was using a FixedSingle  border style on the control...does that change what I'll need to do in order to fix it?

    -Thx
    Monday, July 2, 2007 5:30 PM
  • Apparently not...using the Padding.Vertical property does the job.

    Thanks!!!
    Monday, July 2, 2007 5:37 PM
  • What if I wanted to extend this control to maintain a max width of 175 pixels (defined through a property), but then shrink if the width of the text is shorter then that?

    For example..
    ---------------
    | Hello World |
    ---------------

    ..would behave *like* auto size, but if I put a long text string in there the wrapping behavior would kick in.

    I tried an implementation based on the existing code:   

    resizeLabel()
    ....

    Size noWrapSize = TextRenderer.MeasureText(Text, Font, new Size(0, 0), TextFormatFlags.SingleLine);
    Size wrapSize = TextRenderer.MeasureText(Text, Font, new Size(MaxWidth, Int32.MaxValue), TextFormatFlags.WordBreak);

    if (wrapSize.Height > noWrapSize.Height)
    ClientSize = new Size(MaxWidth, wrapSize.Height + Padding.Vertical);
    else
    ClientSize = new Size(noWrapSize.Width + Padding.Horizontal, noWrapSize.Height + Padding.Vertical);

    ...

    Unfortunately, the characters in the single line case are being truncated on the right side.

    I get something like this:

    -------------
    | Hello Wor |
    -------------

    Any thoughts?

    -Thx
    Monday, July 2, 2007 5:56 PM
  • Make these changes:

      private bool mGrowing;
      private int mMaxWidth;
      public GrowLabel() {
        this.AutoSize = false;
        mMaxWidth = 150;
      }
      [DefaultValue(150)]
      public int MaxWidth {
        get { return mMaxWidth; }
        set { mMaxWidth = value; resizeLabel(); }
      }
      private void resizeLabel() {
        if (mGrowing) return;
        try {
          mGrowing = true;
          Size sz = new Size(mMaxWidth, Int32.MaxValue);
          sz = TextRenderer.MeasureText(this.Text, this.Font, sz, TextFormatFlags.WordBreak);
          if (sz.Height > this.Font.Height) sz = new Size(mMaxWidth, sz.Height);
          this.ClientSize = new Size(sz.Width + this.Padding.Horizontal, sz.Height + this.Padding.Vertical);
        }
        finally {
          mGrowing = false;
        }
      }
      // Rest is the same...

    Note that the resizing handles are no longer useful.  That would take a new designer for the control, a bit too steep to tackle here.
    Monday, July 2, 2007 7:32 PM
    Moderator
  • Hmmm...I'm still seeing the right side of the text being truncated in the "single line" scenario.

    Is there something else I could be missing?

    -Thx
    Monday, July 2, 2007 8:06 PM
  • Hello again!
    You probably forgot about this thread! it has been a long time.. but im currently trying to do the exact same thing you tried to do earlier.

    I just tried your suggested solution and put the label properties as follows:
    • Anchor: Top|Bottom|Left|Right
    • AutoSize: True
    • Dock:None
    But this didnt help! the text was written on 1 line only and it didnt wrap!
    So can you please provide me with the tablelayoutpanel properties that you used? maybe the label properties alone are not enough...

    Thanks
    Sila
    Tuesday, October 14, 2008 11:42 AM
  • if (mGrowing) return; but mGrowing is not initialized, it must be false ? private bool mGrowing = false; ?
    Tuesday, November 11, 2008 1:14 AM
  • sorry it's already false;
    Tuesday, November 11, 2008 1:39 AM
  • why put:
    "mGrowing = true;

    Size sz = new Size(this.Width, Int32.MaxValue);
    sz = TextRenderer.MeasureText(this.Text, this.Font, sz, TextFormatFlags.WordBreak);
    this.Height = sz.Height;

    in try{ }" ?

    TextRenderer.MeasureText method not throw exception

    Tuesday, November 11, 2008 3:46 AM
  • It doesn't?  Every .NET method can throw.  NullRef and ThreadAbort at a minimum.
    Tuesday, November 11, 2008 4:40 AM
    Moderator
  • sorry I begins and i look in msdn website the function that is in the "try":

    Size sz = new Size(mMaxWidth, Int32.MaxValue);
    http://msdn.microsoft.com/en-us/library/system.windows.size.aspx

    sz = TextRenderer.MeasureText(this.Text, this.Font, sz, TextFormatFlags.WordBreak);
    http://msdn.microsoft.com/en-us/library/8wafk2kt.aspx

    this.Height = sz.Height;
    http://msdn.microsoft.com/en-us/library/system.windows.forms.control.height.aspx

    and in these URLs, these functions have no exceptions.
    where can i learn what you say (the reason for putting them in a "try") ?

    please

    (sorry for my english i'm french)
    Tuesday, November 11, 2008 7:08 PM
  • Please start your own thread.  I'd suggest: "Can TextRenderer.MeasureText() throw an exception?" as the title.
    Tuesday, November 11, 2008 9:12 PM
    Moderator
  • hello, I'm really sorry I can not make it work.
    if you want you can download the project here: http://filebin.ca/kzygzg/GrowLabel.rar
    I tested two ways but I can not resize the GrowLabel in the designer of visual studio and after when the soft run but autoSize is false...
    for the inheritance i read http://msdn.microsoft.com/en-us/library/5h0k2e6x.aspx
    thank you very much
    Thursday, February 5, 2009 6:35 AM
  • Your TestLabel2 project works fine when I try it after a full rebuild.  You are not supposed to be able to resize in the label in the designer.  Just the width, the height is set automatically.
    Hans Passant.
    Thursday, February 5, 2009 11:03 AM
    Moderator
  • it does not work for me :(
    http://img7.imageshack.us/img7/742/jeudi05fvrier09175358bj4.png
    Thursday, February 5, 2009 4:41 PM
  • Debug it.  Check the value that MeasureText returns.
    Hans Passant.
    Thursday, February 5, 2009 6:10 PM
    Moderator
  • sorry it's good it's just beacause it's in WordBreak
    it is possible to be in character and not the word ?
    Thursday, February 5, 2009 6:16 PM
  • This is an old thread with many diffrent aspect on how to fix problem with label that has to wrap text.
    I just change the maximumsize (width & height ) in properties for the  label.
    Thursday, March 12, 2009 8:12 AM
  • There's an issue here, however, if there's a long bit of text without spaces, such as a file path that is wider than the width of the label. What happens in this case is that MeasureText will come back with a size that has a width greater than what your label can accomodate, thinking that the path has to reside all on one line. MeasureText, when used with TextFormatFlags.WordBreak, doesn't take into account wrapping too-long text on character boundaries, which is how the label will wrap the text.

    So, by just using the height returned by MeasureText and ignoring the width, your label ends up sized one line too short in height for each time the label control does a wrap on a character boundary.

    It'd be nice if you could tell MeasureText to constrain its returned size to a particular width, but as soon as it encounters a wide string without spaces it nonchalantly tells you that more width is needed --- not knowing or caring that your UI doesn't have horizontal space to spare.

    UPDATE: It appears that if one uses "TextFormatFlags.WordBreak | TextFormatFlags.TextBoxControl" rather than just "TextFormatFlags.WordBreak" in the call to MeasureText, MeasureText will in fact calculate the line breaks the same way as the Label or TextBox control. Hope this helps the next guy who bumps in to this.
    • Edited by Dave Ruske Thursday, August 20, 2009 9:34 PM Possible Solution
    • Proposed as answer by evidence-is-king Friday, August 1, 2014 3:34 AM
    Thursday, August 20, 2009 7:56 PM
  • There's an issue here, however, if there's a long bit of text without spaces, such as a file path that is wider than the width of the label. What happens in this case is that MeasureText will come back with a size that has a width greater than what your label can accomodate, thinking that the path has to reside all on one line. MeasureText, when used with TextFormatFlags.WordBreak, doesn't take into account wrapping too-long text on character boundaries, which is how the label will wrap the text.

    So, by just using the height returned by MeasureText and ignoring the width, your label ends up sized one line too short in height for each time the label control does a wrap on a character boundary.

    It'd be nice if you could tell MeasureText to constrain its returned size to a particular width, but as soon as it encounters a wide string without spaces it nonchalantly tells you that more width is needed --- not knowing or caring that your UI doesn't have horizontal space to spare.

    UPDATE: It appears that if one uses "TextFormatFlags.WordBreak | TextFormatFlags.TextBoxControl" rather than just "TextFormatFlags.WordBreak" in the call to MeasureText, MeasureText will in fact calculate the line breaks the same way as the Label or TextBox control. Hope this helps the next guy who bumps in to this.
    Indeed, a very helpful update. Thanks !
    Monday, February 22, 2010 1:18 PM
  • Sorry, I couldn't help reading this post and answering my solution, which is to use a richtextbox control, set readonly to true, set borderstyle to none, and "VOILA!" you have a label that will wrap and it looks just like any other label out there.  Much simpler then adding a custom control!  Hope this helps someone!
    • Proposed as answer by aandrewd Monday, January 30, 2012 1:29 PM
    Tuesday, March 15, 2011 2:45 PM
  • Testcase:

    GroupBox - AutoSize=True; Dock=Top;

    GroupBox Contains:

    TableLayoutPanel - ColumnCount=1; RowCount=2; AutoSize=True; Dock=Top;

    TableLayoutPanel  ontains:

    First Row: Autosize; Contains Label; AutoSize=True;

    Second Row: Autosize; Contains Button.

    When the content of the Label doesn't fit into a single line of text, the GroupBox doesn't Autosize correct (it becomes to short; exactly one line of text to be exact); so you only see part of the Button.

     

    Solution:

    Public Class GrowLabel
        Inherits Label
    
        Private Function ParentIsTableLayoutPanelOrFlowLayoutPanel() As Boolean
            If Me.Parent Is Nothing Then Return False
            If TypeOf (Me.Parent) Is TableLayoutPanel Then Return True
            If TypeOf (Me.Parent) Is FlowLayoutPanel Then Return True
            Return False
        End Function
    
        Public Overrides Function GetPreferredSize(proposedSize As System.Drawing.Size) As System.Drawing.Size
            Dim Result As System.Drawing.Size = MyBase.GetPreferredSize(proposedSize)
    
            If Me.AutoSize AndAlso Me.ParentIsTableLayoutPanelOrFlowLayoutPanel AndAlso (Me.Text <> String.Empty) Then
                Dim sz As New Size(Me.Width - Me.Margin.Horizontal, Int32.MaxValue)
                sz = TextRenderer.MeasureText(Me.Text, Me.Font, sz, TextFormatFlags.WordBreak Or TextFormatFlags.TextBoxControl)
                sz.Height += Me.Margin.Vertical
    
                If Result.Height < sz.Height Then Result.Height = sz.Height
            End If
    
            Return Result
        End Function
    End Class
    
    


    Friday, November 11, 2011 2:18 PM
  • You may have better results if you use  AutoSize:False.

     

    You can then size the maximum absolute size the label can take up. By using Text-Align, you can set where the wrapping text is fit into the label. 

    Sunday, November 27, 2011 11:43 PM
  • Sorry, I couldn't help reading this post and answering my solution, which is to use a richtextbox control, set readonly to true, set borderstyle to none, and "VOILA!" you have a label that will wrap and it looks just like any other label out there.  Much simpler then adding a custom control!  Hope this helps someone!

    Haha just scrolled through this thread with a growing sense of dismay as it became abundantly clear that labels are no use for the purpose I needed them for and I haven't the time to begin creating custom controls as I'm rebuilding this application from the ground up in less than a week!

    Then I came across abby5's response and kicked myself... talk about a back-to-basics approach. Nailed it for me. Thanks Abby!

    • Proposed as answer by KermRock Monday, December 2, 2013 7:52 PM
    Monday, January 30, 2012 1:35 PM
  • I used the following in my VB code of my asp.net web app:

    Label1.Text = Replace(MessageText, vbNewLine, "<br>") 
    MessageText is, of course, my label text which may or may not contain newlines.
    Monday, December 2, 2013 10:14 PM
  • I'm the "next guy" that this update helped. Even if 5 years later. Thank you for posting your fix!
    Friday, August 1, 2014 3:35 AM