c# com object cant get ref object values

Question

We are trying to get values returned from a COM object, the function is:

bool AxSB100BPC.GetEnrollData(int dwMachineNumber,
int dwEnrollNumber,
int dwEMachineNumber,
int dwBackupNumber,
ref int dwMachinePrivilege,
ref object dwEnrollData,
ref int dwPassWord

We are calling this function as:

vRet = axSB100BPC1.GetEnrollData(mMachineNumber,
                                 vEnrollNumber,
                                 vEMachineNumber,
                                 vFingerNumber,
                                 ref vPrivilege,
                                 ref oglngEnrollData,
                                 ref glngEnrollPData);

The problem is with oglngEnrollData which is type of ref object. It is declared as object oglngEnrollData;.

The error is:

System.Runtime.InteropServices.COMException was unhandled
HResult=-2147352571
Message=Tür uyuşmazlığı. (Exception from HRESULT: 0x80020005 (DISP_E_TYPEMISMATCH))
Source=mscorlib
ErrorCode=-2147352571
StackTrace:
   at System.RuntimeType.ForwardCallToInvokeMember(String memberName,           BindingFlags          flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
   at SB100BPCLib._DSB100BPC.GetEnrollData(Int32 dwMachineNumber, Int32 dwEnrollNumber, Int32 dwEMachineNumber, Int32 dwBackupNumber, Int32& dwMachinePrivilege, Object& dwEnrollData, Int32& dwPassWord)
   at AxSB100BPCLib.AxSB100BPC.GetEnrollData(Int32 dwMachineNumber, Int32 dwEnrollNumber, Int32 dwEMachineNumber, Int32 dwBackupNumber, Int32& dwMachinePrivilege, Object& dwEnrollData, Int32& dwPassWord)
   at enrolldata.Form1.button2_Click(Object sender, EventArgs e) in f:\enrolldata\Form1.cs:line 196
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at enrolldata.Program.Main() in f:\enrolldata\Program.cs:line 19
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

Any ideas are welcomed

Crappy manual. I'd guess at byte[] that's 1416 elements long or an int[] that's 354 elements long. secubio.com/upload/file/1292045533.pdf Call the vendor if you can't figure it out. — Hans Passant
Thank you @HansPassant, it seems 354 for my case; ` const int DATASIZE = 354; //(1404 + 12) / 4;` — kayhan yüksel

Mike Zboray Mike Zboray · Accepted Answer · 2013-02-11T02:02:05

This question on another forum seems to be dealing the same problem for the same interface.

This is just a guess based on that thread, but the problem seems to be that the dwEnrollData parameter is actually a variant type (not a managed System.Object type) in which case you should try using System.Runtime.InteropServices.VariantWrapper to wrap the parameter value you are passing into the method.

c# com object cant get ref object values

1 Answers