Solved

Referencing dll's and ActiveX exe's - (more pts for a solution)

Posted on 2001-06-20
14
267 Views
Last Modified: 2010-05-02
Can project references to dll's or ActiveX exe's be modified dynamically in Vb, I seem to remember they can in Access using Vba. Eg if my compiled exe references a dll or ActiveX exe on one server can I change the reference to a dll or ActiveX exe on another server?

More points if there is a solution and the answer is more than 'no'.
0
Comment
Question by:rhubarbtwo
  • 4
  • 3
  • 2
  • +4
14 Comments
 
LVL 5

Expert Comment

by:rkot2000
Comment Utility
I think you can use late binding to do this.

0
 
LVL 4

Expert Comment

by:beckingh
Comment Utility
Right.  Just don't make your project reference a specific DLL or EXE.  Then in your code, create the object like this:

Set myObj = CreateObject("MyObj.ObjectName")

Obviously, you can pass in a string to "CreateObject", so you can modify it as necessary.

This is Late Binding.
0
 
LVL 1

Expert Comment

by:mcbeth
Comment Utility
you have to unregister the dll and then register the dll you like to use. Windows stores the information where to find the dll local. e.g. if you register a dll not local Windows create a fake Interface und forward all requests to the dll (called proxy stub).  
0
 
LVL 15

Expert Comment

by:ameba
Comment Utility
You can also use Early binding.
You don't need reference to the actual ActiveX DLL or EXE, you only need reference to interface it implements.
0
 
LVL 9

Expert Comment

by:Valliappan AN
Comment Utility
If you are talking about different OS, or specific servers, then you could also, use compiler directives for declaration, if I am right.

Cheers
0
 
LVL 3

Expert Comment

by:Hornet241
Comment Utility
You can use the create object function

Set Obj = CreateObject("MyObj.ObjectName", "MyServerName")

I have used this on a W2K server with the object in a Com+ application, I think it should work with an MTS object as well
0
 

Author Comment

by:rhubarbtwo
Comment Utility
So I can dynamically reference a dll if I don't reference a specific DLL in the references dialog and if I use late binding with method CreateObject. But Windows has to know about the object name (MyObj.ObjectName) so that dll has to be registered with Windows.

Now if I have the dll or activeX exe located on 2 different servers and the file name is identical, could I differentiate between dll's, eg depending on a parameter could I instantiate either 1 of the 2 dll's? I can't see how I can because when the dll's are registered with Windows using a proxy stub the dll's would have identical class names.
0
Do You Know the 4 Main Threat Actor Types?

Do you know the main threat actor types? Most attackers fall into one of four categories, each with their own favored tactics, techniques, and procedures.

 
LVL 5

Expert Comment

by:rkot2000
Comment Utility
try to use :
CreateObject(prodname.classname, location)

prodname.classname
Required.The type or class of the object to create.

location

Optional. The name of the network server where the object is to be created.

0
 
LVL 15

Expert Comment

by:ameba
Comment Utility
' Early bound sample 1
' add reference to whichever MyObj.dll you want
Dim Obj As MyObj.ObjectName
Set Obj = CreateObject("MyObj.ObjectName", "MyServerName")


' Early bound sample 2
' add reference to whichever MyObj.dll you want, or reference to other dll or type library which contains declaration for interface IObjectName

Dim Obj As SomeDll.IObjectName
Set Obj = CreateObject("MyObj.ObjectName", "MyServerName")
(where MyObj.ObjectName implements IObjectName interface)
or:
Set Obj = CreateObject("TheObj.WhatEver", "MyServerName")
(where TheObj.WhatEver implements IObjectName interface)
0
 
LVL 3

Expert Comment

by:Hornet241
Comment Utility
One thing to remember when using the server parameter with the createobject function is that the DLL must be registered on both the Calling machine and the server.

>>>Now if I have the dll or activeX exe located on 2 different servers and the file name is identical, could I differentiate between dll's, eg depending on a parameter could I instantiate either 1 of the 2 dll's?

 If the class id of the DLL is the same all around then the Servername will determine the location it is created

One other thing the DLL does not have to reside on the calling machine, it just has to be registered
0
 
LVL 3

Expert Comment

by:Hornet241
Comment Utility
Forgot to mention that you only register the DLL once on the calling machine, the physical location does not matter as when the Servername parameter is use it does not even look for the file just the class id in the registry
0
 

Author Comment

by:rhubarbtwo
Comment Utility
Thanks everyone for your help, I think Hornet241's comments have been the most help to my specific problem.

Hornet: how do I register a dll on the calling machine when the dll is located on a server? Do I run regsvr.exe on the client with a path to the dll on the server as the argument?
0
 
LVL 3

Accepted Solution

by:
Hornet241 earned 50 total points
Comment Utility
That will work.

You can also copy the DLL using Windows Explorer from the Server and paste it on top of "regsvr32.exe", also you could drag the DLL and drop it on the "regsrv32.exe".  

All of these ways will work when done from the machine you want to register it on.

0
 

Author Comment

by:rhubarbtwo
Comment Utility
Thanks, that's interesting
0

Featured Post

Maximize Your Threat Intelligence Reporting

Reporting is one of the most important and least talked about aspects of a world-class threat intelligence program. Here’s how to do it right.

Join & Write a Comment

Have you ever wanted to restrict the users input in a textbox to numbers, and while doing that make sure that they can't 'cheat' by pasting in non-numeric text? Of course you can do that with code you write yourself but it's tedious and error-prone …
Article by: Martin
Here are a few simple, working, games that you can use as-is or as the basis for your own games. Tic-Tac-Toe This is one of the simplest of all games.   The game allows for a choice of who goes first and keeps track of the number of wins for…
As developers, we are not limited to the functions provided by the VBA language. In addition, we can call the functions that are part of the Windows operating system. These functions are part of the Windows API (Application Programming Interface). U…
Get people started with the process of using Access VBA to control Excel using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Excel. Using automation, an Access application can laun…

771 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now