Q229756: INFO: Maximum Number of Controls on a Form

Article: Q229756
Product(s): Microsoft Visual Basic for Windows
Version(s): 6.0
Operating System(s): 
Keyword(s): kbVBp600 kbGrpDSVB kbFAQ kbDSupport kbVBp600FAQ
Last Modified: 13-AUG-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, version 6.0 
- Microsoft Visual Basic Professional Edition for Windows, version 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 6.0 
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SUMMARY
=======

This articles discusses the number of controls you can add to a form in a Visual
Basic project and ways to work around these limitations.

MORE INFORMATION
================

The maximum number of controls allowed on a single form depends on the type of
controls used and available system resources. However, there is a fixed limit of
254 control names per form.

NOTE: Although you can have up to 254 control names in a form, a large number of
controls in a form will severely degrade your program's performance. In some
cases, you will experience out-of-memory error. To maximize the performance of
your program, you should minimize the number of controls in each form.

Here are three ways to work around the control name and system resource
limitations:

- Use a control array - instead of using several instances of a control in a
  form, create a control array for all the similar controls on the form.
  Members of a control array share the same control name.

- Dynamically create the controls as required - instead of loading all the
  controls on a form when you first display the form, try loading the controls
  as needed. This only works well when you potentially need many controls, but
  will use only a few of them at any given time. For more information about
  dynamically creating controls, please see the following article in the
  Microsoft Knowledge Base:

  Q190670 HOWTO: Dynamically Add Controls to a Form with Visual Basic 6.0

- Put your controls on a UserControl - similar to using a control array, you
  can create a UserControl that contains your controls and then add the
  UserControl to your project. For example, if you need a form that displays
  500 text boxes, create a UserControl that contains 250 text boxes, and put
  two instances of your UserControl on the form. You now have 500 text boxes on
  the form, but only two controls.

REFERENCES
==========

For more information about project, control, and code limitations in Visual
Basic, please see the following topics in the Visual Basic Programmers Guide,
the Online Help, or the MSDN Web site:

  Project Limitations
  http://msdn.microsoft.com/library/en-us/vbcon98/html/vbconprojectlimitations.asp

  Control Limitations
  http://msdn.microsoft.com/library/en-us/vbcon98/html/vbconcontrollimitations.asp

  Code Limitations
  http://msdn.microsoft.com/library/en-us/vbcon98/html/vbconcodelimitations.asp

  Data Limitations
  http://msdn.microsoft.com/library/en-us/vbcon98/html/vbcondatalimitations.asp

  System Resource Limitations
  http://msdn.microsoft.com/library/en-us/vbcon98/html/vbconwindowslimitations.asp

Additional query words: vbFAQProgramming

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Keywords          : kbVBp600 kbGrpDSVB kbFAQ kbDSupport kbVBp600FAQ 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB600Search kbVB600
Version           : :6.0
Issue type        : kbinfo

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