检查可观察的集合是否为空！ C＃

Question

want to check if there are ant Items in an observable collection named PlayerProfile

if ((App.ViewModel.PlayerProfile.Count != 0))
{
  // remove stored PlayerProfile
}

Anyideas ??

gettign a null error (even though there are

App.ViewModel.PlayerProfile is an oberservable collection containg players

i just want to check to see if its empty and if not delete or clear

Answer 1

If you're getting a null error, there are three possibilities:

1. App is null (very unlikely)
2. App.ViewModel could be null.
3. The PlayerProfile property on ViewModel may be null.

I suggest making sure that PlayerProfile is being constructed in all constructors of your ViewModel, and that your ViewModel has been constructed at this point, as those are the most likely culprits. Most likely, this routine is being called prior to your initialization methods, which is why these are unset at this point.

Answer 2

The Count property will return the number of elements in the collection.

However, if you're getting a null error, that means something is null.

Answer 3

App ， ViewModel或PlayerProfile为null 。