Windows service operation throws error: Operation is not valid due to the current state of the object.

[Zeya]

I have this code, which uses WMI to operate on Windows service from C#
code.

When Service.InvokeM ethod is called, the method throws an exception:
System.Manageme nt Operation is not valid due to the current state of
the object. at System.Manageme nt.ManagementOb ject.InvokeMeth od(String
methodName, Object[] args)
Here is the method.

RequestStatus is Enum type defined in the class.

ServerName - Machine where the service might be running

ServiceName - Service name on which the operation is to be performed

OpInstructions - Operation to be performed ( StartService,
StopService )

I have tried Start, StartService, RestartService, Stop, StopService.
None have worked.

Services I tried these actions on: Alerter, Messenger, MSSQLSERVER.

Any ideas whats going wrong? Thanks.

public static RequestStatus OperateService ( string ServerName, string
ServiceName, string OpInstructions )

{

ConnectionOptio ns Options = new
ConnectionOptio ns();

Options.EnableP rivileges = true;

//Service name space: \root\cimv2

ManagementScope Scope = new
ManagementScope ( @"\\" + ServerName + @"\root\cimv 2", Options );

Scope.Connect() ;

if ( Scope.IsConnect ed )

{

ObjectQuery Query = new
ObjectQuery( "SELECT State FROM Win32_Service WHERE Name = '" +
ServiceName + "'" );
ManagementObjec tCollection Services = new ManagementObjec tSearcher (
Scope, Query ).Get();

if ( Services.Count > 0
)

{

foreach (
ManagementObjec t Service in Services )

{
Service.InvokeM ethod( OpInstructions, null );

}

return
RequestStatus.Y es;

}

else

{

return
RequestStatus.N otFound;

}
}

return RequestStatus.N o;

}

[Zeya]

Found the problem. My WQL query was wrong. It needed Name.

SELECT State, Name FROM Win32_Service WHERE Name = '" +
ServiceName + "'"