"Object not set to instance of an object " why am I getting this error

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So I have a validator in the aspx page

ASP.NET

<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="RequiredFieldValidator" Enabled="True"  ControlToValidate="Date"  >

in the code behind I want do disable it base on the role of the user

C#

if (User.IsInRole("Admin"))
 {
 RequiredFieldValidator cecvaliddate = (RequiredFieldValidator)FindControl("RequiredFieldValidator1");

 cecvaliddate.Enabled = false;

 }

when I run this I get the error

"Sys.WebForms.PageRequestManagerServerErrorException: An error occured during the request: Object reference not set to an instance of an object."

Highlighting the line

C#

"cecvaliddate.Enabled = false;"

By the way this is with Visual studio 2010

Posted 23-Jul-15 7:30am

Member 11520626

Updated 23-Jul-15 7:47am

Wendelius

v5

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ZurdoDev 23-Jul-15 13:40pm

FindControl did not find the control. Why you findcontrol? Just do RequiredFieldValidator1.Enabled = false;

Member 11520626 23-Jul-15 13:52pm

If I do that I get an error saying, it doesn't exist in current context

ZurdoDev 23-Jul-15 13:53pm

Is it in some sort of repeater control? If so, you're right, you have to use FindControl. BUt you'll want to use repeater1.FindControl. FindControl() by itself is on the page and your control is not a direct child of the page.

Member 11520626 23-Jul-15 13:56pm

It's inside a formview inside an updatepanel. I tried (RequiredFieldValidator)Formview.FindControl("RequiredFieldValidator1"); but same error "Sys.WebForms.PageRequestManagerServerErrorException: An error occured during the request: Object reference not set to an instance of an object."

ZurdoDev 23-Jul-15 14:02pm

I can't see what you have done nor can I test what you have done. All I can tell you is that you need to try it's direct parent.FindControl(). BUt if the direct parent is itself in another context then you may need to use multiple FindControls to get down to it. It's annoying, but you'll have to figure it out.

F-ES Sitecore 23-Jul-15 13:54pm

You haven't given the full context of your code. The control is not inside the same context as your code-behind is running, so the control is either in a master page\content page\grid view etc etc etc, so depending on where the control sits in relation to your code-behind depends on how you find it. You'll need to explain where this target control is in relation to the page.

Member 11520626 23-Jul-15 14:35pm

It's inside a formview, inside an update panel, inside an EditItemTemplate

F-ES Sitecore 23-Jul-15 16:04pm

EditItemTemplate on what? This might surprise you, but the exact structure of your controls is vital to the solution to your problem. If you don't want to tell us explicitly what your mark-up is then the only advice we can give is to use FindControl on each parent, so if you have

A->B->C

then to get C you need A.FindControl("B").FindControl("C"). If something is inside a template control things can get more complicated, you might need to look inside child collections of the control but as you refuse to properly describe your problem that's as much as we can say.

Finding controls

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Sergey Alexandrovich Kryukov · Answer 1 · 2015-07-23T08:50:00

If your observations a correct, this is because cecvaliddate is of some reference type and this variable or member is null reference. Look, you cannot ask similar questions each time you face such situation, so you need to learn very well how do deal with them all by yourself.

Not to worry. This is one of the very easiest cases to detect and fix. It simply means that some member/variable of some reference type is dereferenced by using and of its instance (non-static) members, which requires this member/variable to be non-null, but in fact it appears to be null. Simply execute it under debugger, it will stop the execution where the exception is thrown. Put a break point on that line, restart the application and come to this point again. Evaluate all references involved in next line and see which one is null while it needs to be not null. After you figure this out, fix the code: either make sure the member/variable is properly initialized to a non-null reference, or check it for null and, in case of null, do something else.

Please see also: want to display next record on button click. but got an error in if condition of next record function "object reference not set to an instance of an object".

Sometimes, you cannot do it under debugger, by one or another reason. One really nasty case is when the problem is only manifested if software is built when debug information is not available. In this case, you have to use the harder way. First, you need to make sure that you never block propagation of exceptions by handling them silently (this is a crime of developers against themselves, yet very usual). The you need to catch absolutely all exceptions on the very top stack frame of each thread. You can do it if you handle the exceptions of the type System.Exception. In the handler, you need to log all the exception information, especially the System.Exception.StackTrace:
http://msdn.microsoft.com/en-us/library/system.exception.aspx,
http://msdn.microsoft.com/en-us/library/system.exception.stacktrace.aspx.

The stack trace is just a string showing the full path of exception propagation from the throw statement to the handler. By reading it, you can always find ends. For logging, it's the best (in most cases) to use the class System.Diagnostics.EventLog:
http://msdn.microsoft.com/en-us/library/system.diagnostics.eventlog.aspx.

Good luck,

—SA