Object reference not set to an instance of an object and INamingContainer

A list of standard ASP.NET web controls that implement INamingContainer

Any control that implements the INamingContainer interface creates a new control namespace which ensures that child controls have unique names on the page. If you try to directly access, for example, a TextBox within a FormView without using the FormView's FindControl() method, you will receive an "Object reference not set to an instance of an object" error. An excellent explanation of this behaviour and the FindControl() method is provided by K Scott Allen, and I won't attempt to replicate the basis of his article here. Instead, here is a list of all the standard ASP.NET web controls (System.Web.UI.Controls) that implement INamingContainer with which the FindControl method needs to be used:

  • ChangePassword
  • CheckBoxList
  • CreateUserWizard
  • DataGrid
  • DataList
  • DetailsView
  • FormView
  • GridView
  • ListView
  • Login
  • LoginView
  • LoginStatus
  • Menu
  • PasswordRecovery
  • RadioButtonList
  • SiteMapPath

There is one addition to the above list - ContentPlaceHolder - when working with MasterPages. For example, to reference a label in a FormView in a ContentPlaceHolder, you need to do something like the following:

Label lbl = this.Content1.FindControl("FormView1").FindControl("Label1") as Label;

Date Posted:
Last Updated:
Posted by:
Total Views to date: 28104


- jkh

Error 8 'Controls' is not a member of 'DataGridTest.iX.Controls.DatePicker'. c:\inetpub\wwwroot\DataGridTest\App_Code_Old\datepicker.vb 21 32

- Mike


As I mentioned next to the comment form you filled in, please make sure that your comments are relevant to the topic being discussed.

I would have emailed you privately with more advice, but your obviously made-up random email address made that impossible. Bit of a waste of your time, really.

- yogesh

thx so much

- ramz

i cannot find the control rangevalidator in formview asp.net using findcontrol.

- Afzaal Ahmad Zeeshan

Hello Mike,

Get article to share views over how to ignore null exception in Web Forms.

Anyways, there is a typo mistake in the code section. You've written two double quotes; (""FormView1"). Remove any one in the beginning. :)

Recent Comments

adam 05/10/2015 14:35
In response to Integrating Web API with ASP.NET Razor Web Pages
Can you re-open this web api project in webmatrix, once you've added web api? Basically I'm looking...

nish 24/09/2015 18:48
In response to Managing Checkboxes And Radios In ASP.NET Razor Web Pages
Very Interresting stuff! it really helped me to send an int value by checking a checkbox!...

Uğur Dinç 24/09/2015 16:45
In response to Scheduled Tasks In ASP.NET With Quartz.Net
Simplest and best explanation on Quartz.NET. Thank you!...

woo 24/09/2015 15:34
In response to Implementing Google's EU End User Consent Policy
Is there any way for the banner to appear only to EU visitors? I am referring to the jQuery code...

Justin 24/09/2015 11:10
In response to Using ASP.NET Identity with Razor Web Pages
Hi Mike, Very helpful article again, thanks. One query that I'm trying to work out is how you to...

hb 23/09/2015 23:12
In response to WebMatrix Opens Wrong Version Of Visual Studio
Mike - I got this working when I went decided to look at the community edition of VS2015 and tried I...

Muneer 22/09/2015 14:55
In response to Scheduled Tasks In ASP.NET With Quartz.Net
I have an error with these two is not recognizing the commands. am i missing any library? I am web...

David 22/09/2015 13:57
In response to iTextSharp - Working with Fonts
Mike your articles about itextsharp are excellent, really helpful and well written. In the future...

Peter 22/09/2015 06:39
In response to Accessing Your Model's Data from a Controller
Thanks.Got it. ...

sreedhar kandukuri 21/09/2015 14:05
In response to Integrating Web API with ASP.NET Razor Web Pages
Nice Overview...