private static IClassFactory GetClassFactoryFromDll(string dllName, string filterPersistClass)
{
//Load the dll
IntPtr dllHandle=Win32NativeMethods.LoadLibrary(dllName);
if (dllHandle==IntPtr.Zero)
return null;
//Keep a reference to the dll until the process\AppDomain dies
_dllList.AddDllHandle(dllHandle);
//Get a pointer to the DllGetClassObject function
IntPtr dllGetClassObjectPtr=Win32NativeMethods.GetProcAddress(dllHandle, "DllGetClassObject");
if (dllGetClassObjectPtr==IntPtr.Zero)
return null;
//Convert the function pointer to a .net delegate
DllGetClassObject dllGetClassObject=(DllGetClassObject)Marshal.GetDelegateForFunctionPointer(dllGetClassObjectPtr, typeof(DllGetClassObject));
//Call the DllGetClassObject to retreive a class factory for out Filter class
Guid filterPersistGUID=new Guid(filterPersistClass);
Guid IClassFactoryGUID=new Guid("00000001-0000-0000-C000-000000000046"); //IClassFactory class id
Object unk;
if (dllGetClassObject(ref filterPersistGUID, ref IClassFactoryGUID, out unk)!=0)
return null;
//Yippie! cast the returned object to IClassFactory
return (unk as IClassFactory);
}
private static IUnknown NewRedemptionObject(Guid guid)
{
//try to set the thread COM apartment
//Thread.CurrentThread.ApartmentState = ApartmentState.STA;
object res = null;
lock (_criticalSection)
{
IClassFactory ClassFactory;
if (_redemptionDllHandle.Equals(IntPtr.Zero))
{
string dllPath;
if (IntPtr.Size == 8)
{
dllPath = DllLocation64Bit;
}
else
{
dllPath = DllLocation32Bit;
}
_redemptionDllHandle = Win32NativeMethods.LoadLibraryW(dllPath);
if (_redemptionDllHandle.Equals(IntPtr.Zero))
{
//throw new Exception(string.Format("Could not load '{0}'\nMake sure the dll exists.", dllPath));
throw new Win32Exception(Marshal.GetLastWin32Error());
}
_dllGetClassObjectPtr = Win32NativeMethods.GetProcAddress(_redemptionDllHandle, "DllGetClassObject");
if (_dllGetClassObjectPtr.Equals(IntPtr.Zero))
{
//throw new Exception("Could not retrieve a pointer to the 'DllGetClassObject' function exported by the dll");
throw new Win32Exception(Marshal.GetLastWin32Error());
}
_dllGetClassObject =
(DllGetClassObject)
Marshal.GetDelegateForFunctionPointer(_dllGetClassObjectPtr, typeof(DllGetClassObject));
}
Object unk;
int hr = _dllGetClassObject(ref guid, ref IID_IClassFactory, out unk);
if (hr != 0)
{
throw new Exception("DllGetClassObject failed with error code 0x" + hr.ToString("x8"));
}
ClassFactory = unk as IClassFactory;
ClassFactory.CreateInstance(null, ref IID_IUnknown, out res);
//If the same class factory is returned as the one still
//referenced by .Net, the call will be marshalled to the original thread
//where that class factory was retrieved first.
//Make .Net forget these objects
Marshal.ReleaseComObject(unk);
Marshal.ReleaseComObject(ClassFactory);
} //lock
return(res as IUnknown);
}
private void Dispose(bool disposing)
{
if (disposing)
{
if (!_dllHandle.Equals(IntPtr.Zero))
{
var dllCanUnloadNowPtr = Win32NativeMethods.GetProcAddress(_dllHandle, "DllCanUnloadNow");
if (!dllCanUnloadNowPtr.Equals(IntPtr.Zero))
{
var dllCanUnloadNow = (DllCanUnloadNow)Marshal.GetDelegateForFunctionPointer(dllCanUnloadNowPtr, typeof(DllCanUnloadNow));
if (dllCanUnloadNow() != 0)
{
return; //there are still live objects returned by the dll, so we should not unload the dll
}
}
Win32NativeMethods.FreeLibrary(_dllHandle);
_dllHandle = IntPtr.Zero;
}
}
}
private static IClassFactory GetClassFactoryFromDll(string dllName, string filterPersistClass)
{
IntPtr dllHandle = Win32NativeMethods.LoadLibrary(dllName);
if (dllHandle == IntPtr.Zero)
{
return(null);
}
_dllList.AddDllHandle(dllHandle);
IntPtr dllGetClassObjectPtr = Win32NativeMethods.GetProcAddress(dllHandle, "DllGetClassObject");
if (dllGetClassObjectPtr == IntPtr.Zero)
{
return(null);
}
DllGetClassObject dllGetClassObject = (DllGetClassObject)Marshal.GetDelegateForFunctionPointer(dllGetClassObjectPtr, typeof(DllGetClassObject));
Guid filterPersistGUID = new Guid(filterPersistClass);
Guid IClassFactoryGUID = new Guid("00000001-0000-0000-C000-000000000046");
Object unk;
if (dllGetClassObject(ref filterPersistGUID, ref IClassFactoryGUID, out unk) != 0)
{
return(null);
}
return(unk as IClassFactory);
}
