Question

Duplicate

Modifying A Collection While Iterating Through It

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Has anyone a nice pattern to allow me to get around the inability to remove objects while I loop through an enumerable collection (eg, an IList or KeyValuePairs in a dictionary)

For example, the following fails, as it modifies the List being enumerated over during the foreach

foreach (MyObject myObject in MyListOfMyObjects) {      if (condition) MyListOfMyObjects.Remove(myObject); } 

In the past I have used two methods.

I have replaced the foreach with a reversed for loop (so as not to change the any indexes I am looping over if I remove an object).

I have also tried storing a new collection of objects to remove within to loop, then looping through that collection and removed the objects from the original collection.

These work fine, but neither feels nice, and I was wondering if anyone has come up with a more elegant solution to the issue

Answer 1

There’s a useful List<T>.RemoveAll(Predicate<T> match) method which I think is designed for this: http://msdn.microsoft.com/en-us/library/wdka673a.aspx