如何遍历ProcessThreadCollection以访问集合中每个对象的属性？

Question

I have a simple loop that attempts to iterate over a ProcessThreadCollection variable

Inside the loop, I am trying to access a property of each object in the collection like so

foreach (var thread in Process.GetProcessesByName(processName)[0].Threads)
{
    var threadId = thread.Id;   

    Console.WriteLine(threadId);   
}

However, I get an error stating the following

Cannot resolve symbol 'Id'

If I do the following, I can access the Id property of an object within the collection

var threadCollection = Process.GetProcessesByName(processName)[0].Threads;

var threadId = threadCollection[0].Id;

Console.WriteLine(threadId);

How could I change my loop so that I could access the Id property of each object in the ProcessThreadCollection ?

Answer 1

Process.Threads property returns ProcessThreadCollection which does not implement generic IEnumerable<T> . Instead, it derives from ReadOnlyCollectionBase , which in turn implements non-generic ICollection and IEnumerable .

Because of all that, when you defined your loop using var the type of the loop variable thread is inferred to be object .

You can work around that in two ways:

Either explicitly specify the type:

foreach (ProcessThread thread in Process.GetProcessesByName(processName)[0].Threads)

or call Cast<ProcessThread> :

foreach (var thread in Process.GetProcessesByName(processName)[0].Threads.Cast<ProcessThread>())

Both of these will make the compiler realize thread is of type ProcessThread and not object and will give you access to all the properties of that type, including Id .