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Getting CLR object property raises Unable to cast COM object of type 'System.__ComObject'

I'm trying to get the value of a property via reflection, but end up getting the following exception:
System.Reflection.TargetInvocationException: 'Exception has been thrown by the target of an invocation.'
Inner Exception:
InvalidCastException: Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Kinect.Interop.INuiColorCameraSettings'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00A4B392-E315-470C-90B7-F7B4C3CE00C4}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).
My code looks like the following, where src is an istance of Microsoft.Kinect.ColorCameraSettings, and propName = "Brightness":
var prop = src.GetType().GetProperty(propName);
if (prop != null)
{
return prop.GetValue(src, null);
}
I've also tried the supposedly more COM-friendly method, but with the same issue:
return src.GetType().InvokeMember(propName, System.Reflection.BindingFlags.GetProperty, null, src, null);
Most interestingly, there is nothing to suggest that src is a COM object:
src.GetType().IsCOMObject returns false
But it seems from the inner exception stack trace that the src object internally interacts with a COM object.
at System.StubHelpers.StubHelpers.GetCOMIPFromRCW(Object objSrc, IntPtr pCPCMD, IntPtr& ppTarget, Boolean& pfNeedsRelease)
at Microsoft.Kinect.Interop.INuiColorCameraSettings.GetBrightness(Double& pBrightness)
at Microsoft.Kinect.NuiColorCameraSettings.GetBrightness()
at Microsoft.Kinect.ColorCameraSettings.get_Brightness()
How can I get the value of this property via reflection at runtime?
Edit: Here is what the Threads window looks like when the exception is thrown
EDIT: Been meaning to update this. Solution here is to run the code on the correct thread, which in this case is a worker from the thread pool. Simply wrapping the call with a Task.Run() works well. The exception (for me at least) isn't very clear about the underlying cause.

Been meaning to update this. Solution here is to run the code on the correct thread, which in this case is a worker from the thread pool. Simply wrapping the call with a Task.Run() works well. The exception (for me at least) isn't very clear about the underlying cause.

I was struggling with getting the property values of a System.__ComObject too.
Initially, the ComObject was a java object with a few properties.
The GetType() solution didn't work for me, so I searched more and found TypeDescriptor as very useful and comfortable.
According to your setup, I think it would be:
if(TypeDescriptor.GetProperties(src).Find(propName, false) != null)
{
propval = TypeDescriptor.GetProperties(src).Find(propName, false).GetValue(src).ToString();
}
Hopefully, it will help someone.

Refer to COM object in the worker thread in C#

I have a COM object SerInterface objCANinterface; which is created in VC++ 6.0 ATL
which i was able to successfully call the methods from my C# GUI.(ThreadingModel is Both when checked in registry)
But i have created a thread which has to use this object opened inside this thread to continues the process.
so i have added the following statements in my constructor class as
public MyClass()
{
// Start the thread with a ParameterizedThreadStart.
ParameterizedThreadStart start = new ParameterizedThreadStart(callBackLoad);
threadFlash = new Thread(start);
threadFlash.SetApartmentState(ApartmentState.STA);
...
}
void myFun()
{
threadFlash.Start(objCANinterface);
threadFlash.Join(); //Wai
}
[STAThread]
public void callBackLoad(object refinterface)
{
//I am not able to access objCANinterface inside my thread so i have passed the object as a parameter and trying to cast
SerInterface objSrinterface = (SerInterface)refinterface;
}
This is not successful Could you please let us know how do i solve this issue. I am getting the following error
An unhandled exception of type 'System.InvalidCastException' occurred in MyClass.exe
Additional information: Unable to cast COM object of type 'System.__ComObject' to interface type 'MYINTERFACELib.SerInterface'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{37C34F3C-0082-46F5-9974-37CEB2E1C2EE}' failed due to the following error: Error loading type library/DLL. (Exception from HRESULT: 0x80029C4A (TYPE_E_CANTLOADLIBRARY)).
Please let me know how to solve this issue. Thanks in advance.
# oberfreak.........
have you tried it by using "as" as well? Wen you step down with a debugger, which type is it, is it the expected type? Are your interops included in the assembly or in a seperate file?
# oberfreak, how do i use "As", could you please let me know how to use that. My interops are included along with my exe. I was able to perfectly work out of the thread.
# Hans Passant:
You forgot to register the type library in your .rgs script and you also didn't create the proxy/stub project. A threading model of Both still requires an object to be marshaled when it was created on an STA thread and used on another STA thread. Which tends to make it pointless to create a new thread. Get ahead by creating the object on the worker thread instead.
# Hans Passant : I have registered my type library and interop also created in the C# which is making me to use inside my C# code.I cannot create a new object as I need to use the same object to continue the CAN sequence commands. Could you please provide any sample for better marshalling inside a thread.

I have unregistered/removed the reference from the Exe and have registered and added the reference back to the tool. Then it worked with the parameter thread passing which made as STA thread. Thanks for the answers proposed.

COM object that has been separated from its underlying RCW cannot be used

I'm write XML AJAX Service with OPC server. XML AJAX Service based on this example.
And I made my service with single attribute:
[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
And next step I'm create class destructor:
~BoilerService()
{
try
{
ReadTimer.Dispose();
group.ReadCompleted -= new ReadCompleteEventHandler(group_ReadCompleted);
group.Remove(true);
server.Disconnect();
}
catch (Exception e)
{
System.IO.StreamWriter sw = new System.IO.StreamWriter("log.txt", true);
sw.WriteLine(DateTime.Now.ToString() +e.Message+ " "+ e.Source+" "+e.StackTrace + " destructor called.");
sw.Close();
sw.Dispose();
}
}
But when I rebuild my solution in VS (files replaced in app path) I get wp3.exe unhandled exception error window (Windows 7). And in Windows event log I see folowing text:
Exception: System.Runtime.InteropServices.InvalidComObjectException
Message: COM object that has been separated from its underlying RCW cannot be used.
StackTrace: at System.StubHelpers.StubHelpers.GetCOMIPFromRCW(Object objSrc, IntPtr pCPCMD, Boolean& pfNeedsRelease)
at OPC.Data.Interface.IOPCServer.RemoveGroup(Int32 hServerGroup, Boolean bForce)
at OPC.Data.OpcGroup.Remove(Boolean bForce)
at OPC.Data.OpcGroup.Finalize()
What did I do wrong?
And VS 2010 give warnings:
1. 'System.Runtime.InteropServices.UCOMIEnumString' is obsolete: 'Use System.Runtime.InteropServices.ComTypes.IEnumString instead. http://go.microsoft.com/fwlink/?linkid=14202'.
2. 'System.Runtime.InteropServices.UCOMIConnectionPointContainer' is obsolete: 'Use System.Runtime.InteropServices.ComTypes.IConnectionPointContainer instead. http://go.microsoft.com/fwlink/?linkid=14202'
May be this error appear because of for this warnings?

According to the MSDN documentation
The finalizers of two objects are not guaranteed to run in any specific order, even if one object refers to the other. That is, if Object A has a reference to Object B and both have finalizers, Object B might have already finalized when the finalizer of Object A starts.
What this means is that if group is elegible for collection at the same time as your OpcGroup instance (which seems very likely) it may well be that group has already been finalised which could easily be the cause of your failure.
It looks like you are coming from a C++ background, in which case you should be aware that finalisers work differently in C# - its very rare that you ever need to implement a finaliser. I would recommend that instead of doing this clean up in your finaliser you instead implement IDisposable and do this work when the object is disposed.
Also you don't normally need to un-hook event handlers (unless the event may still be fired and could cause an exception after an object has ben disposed). This sort of clean up is handled for you.

Marshal.ThrowExceptionForHR throws a NotSupportedException

im using the following pattern for translating win32 exceptions into .NET exceptions.
var result = A_KERNEL32_PINVOKE_CALL();
if (result == 0)
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
For completeness the pinvoke call is one of the following: LoadLibrary, GetProcAddress, SetWindowsHookEx.
This works well most of the time, throwing exceptions like this one:
System.ArgumentException: Argument out of range.
at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
But sometimes I get the following exception:
System.NotSupportedException: This Stream does not support seek operations.
at System.Net.ConnectStream.get_Position()
at System.Net.WebClient.WebClientWriteStream.get_Position()
at System.Drawing.UnsafeNativeMethods.ComStreamFromDataStream.Seek(Int64 offset, Int32 origin)
at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
I can't think of a reason for this exception. Please note that the stack trace doesn't start with ThrowExceptionForHRInternal like the first exception. Hence I think this might be a exception of the ThrowExceptionForHR method itself.
EDIT: Please note that I'm not calling any Stream methods directly. However the code is executed in a thread pool thread, so there might be other code in the same thread using Stream methods.
Any suggestions how to solve this issue?
UPDATE: I just found out, that the stack trace
at System.Net.ConnectStream.get_Position()
at System.Net.WebClient.WebClientWriteStream.get_Position()
at System.Drawing.UnsafeNativeMethods.ComStreamFromDataStream.Seek(Int64 offset, Int32 origin)
belongs to a call to Image.Save(Stream, Format). There a the NotSupportedException is caught. These code peaces are completely independant, but maybe they are executed on the same thread pool thread.
So why does this exception influence my code in another method?

By now I think, that I misused the Marshal.ThrowExceptionForHR() method. I suppose that it's not intended to be used with a Win32 call. My interpretation of the behavior is, that the function uses context information of the current thread to gather more details about the exception. See this blog for a similar problem.
In my case the issue can be solved by creating my own ThrowExceptionForWin32ErrorCode(errorCode) method.
Please keep answering, if you got a better solution.

I don't know why ThrowExceptionForHRInternal tries to manipulate some stream.
While call stack looks strange, consider not passing stream directly from Web response to drawing functions which seem to cause exception in your case but copy data to memory stream first. This will likely allow you to see what original problem is (as ThrowExceptionForHRInternal will no longer fail trying to manipulate a stream).

exception call stack truncated without any re-throwing

I have an unusual case where I have a very simple Exception getting thrown and caught in the same method. It isn’t re-thrown (the usual kind of problem naïve programmers have). And yet its StackFrame contains only one the current method. Here’s what it looks like:
at (my class).MyMethod() in C:\(my file path and line)
In reality there are probably 30 methods leading up to this in the VS2010 debugger's call stack, going across half a dozen different assemblies. It seems impossible for all that to have been optimized out. Moreover, this code is built in debug mode, without optimizations, for .NET 4. I even have (based on http://msdn.microsoft.com/en-us/library/9dd8z24x.aspx) .ini files (including one named [app].vshost.ini) in the same folder containing:
[.NET Framework Debugging Control]
GenerateTrackingInfo=1
AllowOptimize=0
Also, the method calls are not at the end of methods, so tail-recursion optimization seems further unlikely.
As to how it is called: there are no uses of reflection on the call stack, no Invoke() or BeginInvoke() of any kind. This is just a long chain of calls from a button click. The click handler is about 10 calls down the call stack. Beneath that you have the usual WndProc, NativeWindow.Callback, native/managed transitions, and message loop. This is ultimately inside a ShowDialog() call which is run from a C# EXE assembly.
Now, I found that I can construct instances of the StackTrace class in my catch handler, and if I pass the Exception object, the call stack is also short. If instead I just call new StackTrace() with no arguments, it yields a complete call stack.
I’ve used Reflector in an attempt to debug into the internals of the Exception class getting thrown and its call stack constructed, but I couldn’t set breakpoints in Exception or in StackTrace. I could set them in Environment.GetStackTrace() and this method (which Exception calls) does not appear to get called during the construction and throwing process, but I don’t know if the debugger is really working properly. (This method does get triggered for some other things though, so I'm not sure what to make of it.)
Here’s an excerpt of the method:
private void MyMethod()
{
...
try
{
throw new ApplicationException("Test failure");
}
catch (Exception e)
{
StackTrace stackTrace1 = new StackTrace(e);
StackTrace stackTrace2 = new StackTrace(e, false);
StackTrace stackTrace3 = new StackTrace(e, true);
StackTrace stackTrace4 = new StackTrace();
string STs = stackTrace1.ToString() + "\n---\n"
+ stackTrace2.ToString() + "\n---\n"
+ stackTrace3.ToString() + "\n---\n"
+ stackTrace4.ToString();
Log(EventSeverity.Debug, STs);
...
}
}
It’s really pretty simple: Throw exception, catch and log it.
I get the same results either in the debugger or when running standalone—a one-line call stack. And I know I have seen this problem elsewhere in our code base. Previously I had assumed it was due to re-throwing exceptions, but in a lot of cases it we log right inside the initial catch block. I’m quite baffled and all the web searching I’ve done hasn’t produce anything.
This is a little too much to add as a comment to the answer provided, but here's some more information:
I now see that this behavior is discussed at
http://dotnetthoughts.wordpress.com/2007/10/27/where-did-my-exception-occur/ and that it is actually described at http://msdn.microsoft.com/en-us/library/system.exception.stacktrace.aspx (though I think one could easily miss what they're saying there).
So I guess my "solution" will be a little hit-or-miss. We have a central method we usually call to format exceptions. Inside that method, I'll create a new StackTrace() both with and without the Exception object. Then I'll look for the method that is at the bottom of the Exception's stack trace, and display everything beneath that in the new StackTrace(), indicating it was called by that series of calls.
The down side of course is that if this method isn't used, the information won't be there. But I had to expect some kind of code change somewhere.

When an exception is thrown, only a partial stack trace will be used in the Exception.StackTrace property. The stack only shows calls up until the method that is catching the exception. To get the full stack (as you have noted) you should create a new StackTrace() object.
I can't find any links on it at the moment but I believe the stack trace is built by walking up the stack while throwing the exception. Once the exception reaches a catch block, the stack stops being compiled. Therefore, you only get a partial stack.
Typically, a catch block is not concerned with who called it, but where the exception is originating from.