How do you handle this exception?

Unhandled Exception: System.Runtime.InteropServices.COMException (0x800706BA): The RPC server is unavailable. at System.Runtime.InteropServices.Marshal.ThrowExcept ionForHR(Int32 errorCode, IntPtr errorInfo) at System.Runtime.InteropServices.Marshal.ThrowExcept ionForHR(Int32 errorCode) at System.Management.ManagementScope.InitializeGuts()

The try/catch block in the following code fragment should handle the above exception but does not. Why?

string[] systems = {"cpu1", "cpu2", "OnLine-
    NotResponding", "off-line"};
ConnectionOptions wmiConnOption;
ManagementObjectSearcher osSearch;
ManagementObjectCollection osInfo;
ManagementScope scope;
ObjectQuery osQuery;
wmiConnOption = new ConnectionOptions();
wmiConnOption.Impersonation = ImpersonationLevel.Impersonate;
osQuery = new ObjectQuery("Select * from Win32_OperatingSystem");
for (int i = 0; i < systems.Length; i++)
{
   scope = new ManagementScope("\\\\" + systems[i] + "\\root\\cimv2",
      wmiConnOption);
   osSearch = new ManagementObjectSearcher(scope, osQuery);
   try
   {
       scope.Connect();
   }
   catch(Exception e)
   {
       Console.WriteLine("Access error: " + e.Source);
   }
   if(scope.IsConnected)
   {
       osInfo = osSearch.Get();
       foreach(ManagementObject osItem in osInfo)
       {
          Console.WriteLine(systems[i] + " OS Version: " + osItem
             ["Version"]);
       }
   }
}

The security context is administrator for the code
and access to the remote systems. For systems "cpu1" & "cpu2" the
code works as expected. System "OnLine-NotResponding" can be
pinged but does not responding to remote access. System "Off-line"
is off-line or may not exist.

The last two systems in the array throw the "Unhandled Exception".

Thanks,
Mike

Here is the complete test app.
The program works if you remove "[STAThread]"
from the code. What does "[STAThread]" do?


using System;
using System.Management;
using System.Collections;

namespace ConnectErr
{
    /// <summary>
    /// Summary description for Class1.
    /// </summary>
    class Class1
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
             //[STAThread] * remove and code works. Why ????
        static void Main(string[] args)
        {
            string[] systems = {"cpu1", "cpu1", "OnLine-NotResponding", "bogusname"};
            ConnectionOptions wmiConnOption;
            ManagementObjectSearcher osSearch;
            ManagementObjectCollection osInfo;
            ManagementScope scope;
            ObjectQuery osQuery;
            wmiConnOption = new ConnectionOptions();
            wmiConnOption.Impersonation = ImpersonationLevel.Impersonate;
            osQuery = new ObjectQuery("Select * from Win32_OperatingSystem");
            for (int i = 0; i < systems.Length; i++)
            {
                scope = new ManagementScope("\\\\" + systems[i] + "\\root\\cimv2", wmiConnOption);
                osSearch = new ManagementObjectSearcher(scope, osQuery);
                try
                {
                    scope.Connect();
                }
                catch(System.Runtime.InteropServices.COMException e)
                {
                    Console.WriteLine("Access error: " + e.Source);
                }
                if(scope.IsConnected)
                {
                    osInfo = osSearch.Get();
                    foreach(ManagementObject osItem in osInfo)
                    {
                        Console.WriteLine(systems[i] + " OS Version: " + osItem["Version"]);
                    }
                }
            }
            Console.ReadLine();
        }
    }
}


- Mike

Hi Mike

A query about STAThread has already been answered at
http://p2p.wrox.com/topic.asp?TOPIC_ID=426

Regards

Ankur Verma
.Net and C++ Specialist
Wiley Tech Support

The [STAThread] Attribute indicates that the code is Single Thread Apartment, or only one thread can be executing the code at a time.

Regards,
Meredtih Shaebanyan