c# - Does the Garbage Collector destroy temporarily unreferenced objects during async calls in .NET?

Question

Imagine that I will make an async call in .NET, i.e. HttpWebRequest.BeginGetResponse, and the HttpWebRequest object isn't referenced at a broader scope. Will the Garbage Collector destroy it and cause problems?

Example code:

using System;
using System.Net;

public class AsyncHttpWebRequest
{
    void Main()
    {
        var Request = HttpWebRequest.Create("http://www.contoso.com");
        var result = Request.BeginGetResponse(GetResponseCallback, null);
    }

    private void GetResponseCallback(IAsyncResult AsyncResult)
    {
        // Do Something..
    }
}

Alternate version (with the request being passed as an AsyncState):

using System;
using System.Net;

public class AsyncHttpWebRequest
{
    void Main()
    {
        var Request = HttpWebRequest.Create("http://www.contoso.com");
        var result = Request.BeginGetResponse(GetResponseCallback, Request);
    }

    private void GetResponseCallback(IAsyncResult AsyncResult)
    {
        // Do Something..
    }
}

Answer 1

An object is considered alive and non-eligible for garbage collection if any live thread contains a reference to it, or if it's referenced statically (directly or indirectly in both cases).

In both examples the async API keeps a reference to your request (within the thread pool where async IO operations are lodged) and so it won't be garbage collected until it completes.