问题
I created a skeleton Active X DLL with its Instancing property set to MultiUse and only one function which does nothing but pop up a message box saying that it has been called.
Then I created a test program and added the DLL to its References.
I added code to declare a variable of the DLL's Classmodule, to create a new object and to call the function.
In all cases I used Intellisense code completion, so VB6 certainly about the DLL and it's class & method.
However, when I run the tester it reports runtime "error 91 object variable or With block variable not set" when trying to create the New object.
This is new territory for me, so hopefully it is something obvious.
Update: I added a message box in a DLL fn() to say that it had been called, then went to a real life web site that uses Active X to call into the DLL and saw the message box - but I still get the error in a VB tester application(!?)
回答1:
It would be easier to find the problem if you could post the calling code and the DLL class.
Here's a guess. Have you remembered the Set on the line that creates the new object?
Correct code
Set obj = New MyDLL.MyObject
Incorrect code
obj = New MyDLL.MyObject
回答2:
Try changing the function in your active x dll to return a message instead. Show your message box in your calling code, not in the dll.
Else, try in command prompt, regsvr32 "myDll.dll", and then run your code.
来源：https://stackoverflow.com/questions/3626540/testing-active-x-dll-runtime-error-91-object-variable-or-with-block-variable-n