PRB: System.InvalidOperationException Error When You Use HttpWebRequest and HttpWebResponse Classes in Application with Thread Pool (815637)

MORE INFORMATION

1. Start Microsoft Visual Studio .NET.
2. On the File menu, point to New, and then click Project.
3. Click Visual Basic Projects or Visual C# Projects under Project Types, and then click Console Application under Templates.
4. Replace the code in the Class1 code window with the following code, depending on your project type:
   
   Visual C# .NET Code

   using System;
   using System.IO;
   using System.Net;
   using System.Text;
   using System.Threading;
   using System.Net.Sockets;
   
   namespace threadTest
   {
     
   	class Class1
   	{
   		 public static void Main()
   		{			
   		// Set number of threads to be created for testing.
   			int testThreads = 55;
   			for(int i=0;i<testThreads;i++)
   			{
   				ThreadPool.QueueUserWorkItem(new WaitCallback(PoolFunc));
   			}
   			Console.ReadLine();
   		}
   
   		static void PoolFunc(object state)
   		{
   			int workerThreads,completionPortThreads;
   			ThreadPool.GetAvailableThreads(out workerThreads,
   				out completionPortThreads);
   			Console.WriteLine("WorkerThreads: {0}, CompletionPortThreads: {1}", 
   			workerThreads, completionPortThreads);
   			Thread.Sleep(10000);
   			
   			string url ="http://www.msn.com";         
   			
   			HttpWebRequest myHttpWebRequest ; 
   			HttpWebResponse myHttpWebResponse=null ;        
   			// Creates an HttpWebRequest for the specified URL.    
   			myHttpWebRequest = (HttpWebRequest)WebRequest.Create(url); 
   			// Sends the HttpWebRequest, and waits for a response.
   			myHttpWebResponse = (HttpWebResponse)myHttpWebRequest.GetResponse();            
   			myHttpWebResponse.Close();
   		}
   	}
   }
   

   Visual Basic .NET Code

   Imports System.IO
   Imports System.Net
   Imports System.Text
   Imports System.Threading
   Imports System.Net.Sockets
   
   Module Module1
   
      Sub Main()
         'Set number of threads to be created for testing.
         Dim testThreads As Integer = 55
         Dim i As Integer
   
         For i = 0 To testThreads
            ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf PoolFunc))
         Next
         Console.ReadLine()
   
      End Sub
      Public Sub PoolFunc(ByVal state As Object)
   
         Dim workerThreads, completionPortThreads As Integer
   
         ThreadPool.GetAvailableThreads(workerThreads, completionPortThreads)
   
         Console.WriteLine("WorkerThreads: {0}, CompletionPortThreads: {1}", workerThreads, completionPortThreads)
         Thread.Sleep(10000)
         Dim url As String = "http://www.msn.com"
         Dim myHttpWebRequest As HttpWebRequest
         Dim myHttpWebResponse As HttpWebResponse = Nothing
         ' Creates an HttpWebRequest for the specified URL. 
         myHttpWebRequest = CType(WebRequest.Create(url), HttpWebRequest)
         'Sends the HttpWebRequest, and waits for a response.
         myHttpWebResponse = CType(myHttpWebRequest.GetResponse(), HttpWebResponse)
         myHttpWebResponse.Close()
      End Sub
   End Module

5. On the Debug menu, click Start to run the application. After the available WorkerThreads reaches 0, you receive the error message that is listed in the "Symptoms" section.