Parallel.Foreach on values (Concurrent Bag) of one key in Concurrent Dictionary

Question

I am having problems converting a ForEach loop into a Parallel.ForEach loop.

I have a Concurrent Dictionary:

private readonly ConcurrentDictionary<string, ConcurrentBag<ParentClass>> ObjectDict = new();

which contains:

• as key: string of object "type"
• as value: a ConcurrentBag of objects of a class which inherited from ParentClass. In the following code it shall be ObjectA.

Object A inherits from ParentClass.

My goal is to cycle through the Concurrent Bag of one Key-Entry in the Concurrent Dictionary.

Now I am struggling to convert the following ForEach Loop to Parallel.ForEach

foreach (ObjectA objA in ObjectDict["Object A"])
{
     objA.ObjectASpecificMethod();
}

To

Parallel.ForEach(ObjectDict["Object A"], objA =>
{
     objA.ObjectASpecificMethod();
}

The problem is that objA is not of type ObjectA but of ParentClass as defined in the Concurrent Dictionary ObjectDict. But ParentClass does not have the Childclass specific Method.

I hope I could clarify myself properly.

Answer 1

You can specify the type, just as you can do in your regular foreach:

    Parallel.ForEach(ObjectDict["Object A"], (ObjectsA objectA) =>
    {
         objectA.ObjectASpecificMethod();
    }