System Null Exception always shows

[Guest]

When I compile and run my application, even thought a form that created by
Designer, my system always shows this error:

Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.

It always happens and I cannot debug to that code, it said the code not
available. Anyone met this problem yet? Who can help me?

My system is Windows XP SP2.

Thanks in advance.

 

[Guest]

Not sure if this helps or not but I just got done tracking the same error
down on my application. The offending code was a property in a custom
control. For some reason the set method was being run at compile time even
though I wasn't directly calling it. I'm guessing this is how .net
intializes components?? In my set property method I had reference to an
object that defaulted to null. Once I put a condition statement in front of
this:

set {
if (foo != null)
....
}

things worked fine.

 

[cody]

Yes, the visual designer initializes *all* properties of a control unless:

- The property is marked with the
[DesignerSerialisationVisibility(DesignerSerialisationVisibility.Hidden)]
attribute

or

- The property is marked with the [DefaultValue(xyz)] attribute and the
property has the value xyz when the object is initialized.

 

[Guest]

Ok, thanks. However, how to solve this problem? It make me tired, at any time
I start my application, it always said like that. I mean all .NET
applications have got the same problem. What can I do here? Reinstall Visual
Studio.Net, Windows XP SP2 or any thing else?

For more information, when I choose debug with CLR and Native it shows:

An unhandled exception of type 'System.NullReferenceException' occurred in
Unknown Module.
Additional information: Object reference not set to an instance of an object.

there is an interested thing:
7C90EB90 nop
7C90EB91 nop
7C90EB92 nop
7C90EB93 nop
7C90EB94 ret <== this line error
7C90EB95 lea esp,[esp]
7C90EB9C lea esp,[esp]

This always happens.