Decrease WMI query execution time

Question

In my application i want to see if windows 7 is activated. To be clear, i do not want to check if windows are genuine. I use the code below, found here http://www.dreamincode.net/forums/topic/166690-wmi-softwarelicensingproduct/

The time needed to execute the query is about 5-10 sec. Is there anyway to reduce the time needed? Or another way to check if winows 7 is activated?

public string VistaOrNewerStatus(){
string status = string.Empty;
string computer = ".";
try
{
    //set the scope of this search
    ManagementScope scope = new ManagementScope(@"\\" + computer + @"\root\cimv2");
    //connect to the machine
    scope.Connect();

    //use a SelectQuery to tell what we're searching in
    SelectQuery searchQuery = new SelectQuery("SELECT * FROM SoftwareLicensingProduct");

    //set the search up
    ManagementObjectSearcher searcherObj = new ManagementObjectSearcher(scope, searchQuery);

    //get the results into a collection
    using (ManagementObjectCollection obj = searcherObj.Get())
    {
        MessageBox.Show(obj.Count.ToString());
        //now loop through the collection looking for
        //an activation status
        foreach (ManagementObject o in obj)
        {

            //MessageBox.Show(o["ActivationRequired"].ToString());
            switch ((UInt32)o["LicenseStatus"])
            {
                case 0:
                    status = "Unlicensed";
                    break;
                case 1:
                    status = "Licensed";
                    break;
                case 2:
                    status = "Out-Of-Box Grace Period";
                    break;
                case 3:
                    status = "Out-Of-Tolerance Grace Period";
                    break;
                case 4:
                    status = "Non-Genuine Grace Period";
                    break;
            }
        }
    }


   // return activated;
}
catch (Exception ex)
{
   // MessageBox.Show(ex.ToString());
    status = ex.Message;
    //return false;
}
return status;

}

Answer 1

I would recommend querying only the properties you really need. So, if you only need the LicenseStatus value of the SoftwareLicensingProduct WMI class then use the following query:

SelectQuery searchQuery = new 
            SelectQuery("SELECT LicenseStatus FROM SoftwareLicensingProduct");

This should improve your performance. As DJ KRAZE pointed out in his answer you should of course dispose your management classes.

On my Windows 7 machine using only the LicenseStatus property in the query took 246ms. Querying for all properties (using the "*") took 2440ms.