Question

I have a .NET application which runs WMI queries on all domain computers in order to find the logged in user; it pings each computer to find whether it is online or not, then runs the actual query.

Code snippet:

try
{
    string loggedonuser = null;

    string computername = "ComputerToQuery";

    ConnectionOptions co = new ConnectionOptions();

    co.Username = "DOMAIN\MyUser";
    co.Password = "MyPassword";

    co.Impersonation = ImpersonationLevel.Impersonate;
    co.Authentication = AuthenticationLevel.Default;

    ManagementPath mp = new ManagementPath(@"\\" + computername + @"\root\cimv2");

    ManagementScope ms = new ManagementScope(mp,co);

    ms.Connect();

    ObjectQuery oq = new ObjectQuery("SELECT username FROM Win32_ComputerSystem");

    ManagementObjectSearcher mos = new ManagementObjectSearcher(ms,oq);

    foreach(ManagementObject mo in mos.Get())
        loggedonuser = (String) mo["username"];
}
catch(Exception e)
{
    // Handle WMI exception
}

The problem: sometimes the WMI query hangs on indefinitely.

How can I set a timeout on it?

Answer 1

The ManagementObjectSearcher has an Options property: one of the available options is Timeout, of type TimeSpan:

Gets or sets the time-out to apply to
the operation. Note that for
operations that return collections,
this time-out applies to the
enumeration through the resulting
collection, not the operation itself
(the ReturnImmediately property is
used for the latter). This property is
used to indicate that the operation
should be performed
semi-synchronously.