C# WMI ManagementException thrown on search.Get().Count

Question

Hello this is my first post on Stackoverflow.

Background: I am building a Class to use the WindowsManagementInstrumentation library to query DNS Servers.

Problem: When I search for a dns record that does not exist on the DNS Server I get the following error: An exception of type 'System.Management.ManagementException' occurred in System.Management.dll but was not handled in user code

It is caused from this line:

            if (search.Get().Count > 0)

In looking at this line I found the exception is on the Count.

I am not sure why this happens. If I search for a DNS Record that I know is on the DNS Server then Count returns the correct number and doesn't throw an error. I expect Count to return 0 if it can't find a DNS Record on the server. I could do a try catch and when it throws the exception handle it on my end so it but I feel this is not the right way to do it. Any ideas?

I get the following error info when I debug.

Count   'Count' threw an exception of type 'System.Management.ManagementException'  int {System.Management.ManagementException}
base    {"Generic failure "}    System.SystemException {System.Management.ManagementException}
base    {"Generic failure "}    System.Exception {System.Management.ManagementException}
Data    {System.Collections.ListDictionaryInternal} System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
    HelpLink    null    string
    HResult -2146233087 int
    InnerException  null    System.Exception

    Message "Generic failure "  string
    Source  "System.Management" string
    StackTrace  "   at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode)\r\n   at System.Management.ManagementObjectCollection.ManagementObjectEnumerator.MoveNext()\r\n   at System.Management.ManagementObjectCollection.get_Count()"   string  
    ErrorCode   Failed  System.Management.ManagementStatus

Full Method:

public List<ManagementObject> GetRecords(string domain, string name, string type)
{
    //Object to hold list of RRecords/DNS Records
    List<ManagementObject> rrecords = new List<ManagementObject>();

    //Init properites for the given type
    Properties propertiesStruct = new Properties(type);

    //Query
    string query = "SELECT * FROM " + propertiesStruct.Table + " WHERE DomainName = '" + domain.ToLower() + "' AND OwnerName ='" + name.ToLower() + "." + domain.ToLower() + "'";

    //Search for results
    ManagementObjectSearcher search = new ManagementObjectSearcher(this.scope, new ObjectQuery(query));

    //Make sure we have something and if we do loop through them to grab the data
    if (search.Get().Count > 0)
    {
        foreach (ManagementObject results in search.Get())
        {
                rrecords.Add(results);
        }
    }
    return rrecords;
}

Sorry if I missed anything and thanks for the help.

Answer 1

Just so anyone else who runs across this knows what I ended up doing. I ended up wrapping the count check in a try catch and if it throws an exception I ignore it and just return an empty rrecords object since the search didn't find anything.