c# - WMI .NET Invalid query -

i keep getting "invalid query" exception when trying execute following query:

managementobjectsearcher searcher = new managementobjectsearcher("select * win32_diskquota quotavolume.deviceid = 'c:'"); managementobjectcollection quotacollection = searcher.get(); 

however works: "select * win32_diskquota".

according msdn:

for uses of class descriptors in clause, wmi flags query invalid , returns error. however, use dot (.) operator properties of type object in wmi. example, following query valid if prop valid property of myclass , type object:

select * myclass prop.embedprop = 5

does mean works if prop declared object?

here exception details:

system.management.managementexception unhandled   hresult=-2146233087   message=invalid query    source=system.management   stacktrace:        в system.management.managementexception.throwwithextendedinfo(managementstatus errorcode)        в system.management.managementobjectcollection.managementobjectenumerator.movenext()        в userquota.program.getquota() в c:\users\administrator\documents\visual studio 2015\projects\userquota\userquota\program.cs:строка 40        в userquota.program.main(string[] args) в c:\users\administrator\documents\visual studio 2015\projects\userquota\userquota\program.cs:строка 33        в system.appdomain._nexecuteassembly(runtimeassembly assembly, string[] args)        в system.appdomain.executeassembly(string assemblyfile, evidence assemblysecurity, string[] args)        в microsoft.visualstudio.hostingprocess.hostproc.runusersassembly()        в system.threading.threadhelper.threadstart_context(object state)        в system.threading.executioncontext.runinternal(executioncontext executioncontext, contextcallback callback, object state, boolean preservesyncctx)        в system.threading.executioncontext.run(executioncontext executioncontext, contextcallback callback, object state, boolean preservesyncctx)        в system.threading.executioncontext.run(executioncontext executioncontext, contextcallback callback, object state)        в system.threading.threadhelper.threadstart()   innerexception:  

yes. according win32_diskquota class documentation, quotavolume property reference win32_logicaldisk wmi class. quotation msdn supplied gave reason why query invalid according wql specs.

instead, can use this:

managementobjectsearcher searcher = new managementobjectsearcher("select * win32_diskquota quotavolume = \"win32_logicaldisk.deviceid=\\\"c:\\\"\""); managementobjectcollection quotacollection = searcher.get(); 

(notice escaping...)