// Do not remove this try catch block.

PIEBALDconsult

At least make it catch only null reference exceptions? And let Bob sort out the rest?

Lost User

Hmmm, I can infer from this snippet that the filters variable is most likely a CString[^] member variable which is being modified/accessed by multiple threads. Am I right? :) Best Wishes, -David Delaune

Bernhard Hiller

I am trying to figure out how that can work. What about

private Something _filters;
private Something filters
{
get
{
if (_filters == null)
{
Task.Run(() => CreateFilters());
}
return _filters;
}
}
private void CreateFilters()
{
// somehow instantiates a Something and sets the _filters member
}

That could cause such a strange behavior, couldn't it? :-D

KBZX5000

Just remove the try-catch and stack-trace the exception. I don't see the problem. o7

Plamen Dragiyski

I think he might not know what Multi-Threaded Programming is.

maze3

OMG that is terrible

try {
Filtering = !filters.IsEmpty;
}
catch(Exception ex) {
// Do not remove this try catch block. For some reason this always throws Null reference exception but then works.
}
finally {
Filtering = !filters.IsEmpty;
}

kristopher baker

My guess is that either "filters" isn't instantiated or is getting instantiated at the same time that it is being called. What is happening when "IsEmpty" is called? It might be trying to kick something off when it is called.

Middle Manager

I second that request. Can we be shown the IsEmpty code please? Can't be too many company secrets hidden in there... god, please say there isn't! :omg:

agolddog

Outside of that... Who knows the context, but I'm going to guess that filters is a private member property, and Filtering is exposed. Why wouldn't someone just make Filtering a public, get-only convenience property then, rather than setting some piece of data, where we now have to maintain two things?

Bernhard Hiller

Exactly. But somewhere he read something about lazy initialization, and somewhere else he saw a Task.Run, understood neither of them, and ... Welcome to the wonderful world of code monkeys who've used every programming concept during their career. :^)

User 11277767

public bool IsEmpty
{
get {
try {
return _filters.IsEmpty();
}
catch (NullReferenceException e)
{
InstantiateFilters();
throw new NullReferenceException("Try it again now please.");
}
}
}

Daniel R Przybylski

Are You A Code Poet? - I'm silently reviewing your code T-Shirt | Teespring[^]

Leng Vang

Zombie coder?

Yusuf

Nope. filter is ICollectionView [^](https://msdn.microsoft.com/en-us/library/system.componentmodel.icollectionview(v=vs.110).aspx) type. It is possible it could be null.

Yusuf May I help you?

Yusuf

var filters = Grid.RecordManager.FilteredInDataItems;

it is using 3rd party grid control. It returns ICollectionView [^](https://msdn.microsoft.com/en-us/library/system.componentmodel.icollectionview(v=vs.110).aspx)

Yusuf May I help you?

Yusuf

bool IsEmpty { get; }

Member of System.ComponentModel.ICollectionView

Yusuf May I help you?

kristopher baker

That tells you everything. You're variously trying to call an IsEmpty() method on a null _filters object. The exception is caught, InstantiateFilters() then fills up your filters variable from your calling code. The next time around in the finally it calls on the IsEmpty property again but this time _filters has been instantiated and the 'try' passes without a problem.

User 11277767

I'm not the OP so I have no knowledge of the actual code. That was just a stupid joke on my part.