whats the similarilty & difference between .dll extension and .exe extension files?

 Posted by Charugoel on 2/4/2009 | Category: .NET Framework Interview questions | Views: 9721

A standard exe application is one that is created using Standard EXE project. It is the most widely used Project type using VB6. Standard EXE application is normally the most widely used among the available Project types in Visual Basic. Stand-alone programs have an .EXE file extension.

Usage A standard EXE application is normally used when you want to develop a stand-alone application. Examples include calculators, text editors, and other similar applications.

An ActiveX EXE application is one that is created using ActiveX EXE project. ActiveX EXE are widely used in conjunction with standard EXE applications. There are three types of widely used of ActiveX projects. These are:

a. ActiveX EXE
b. ActiveX DLL
c. ActiveX Control

ActiveX EXE: Unlike a stand-alone EXE file, an ActiveX EXE file is designed to work as an OLE server, which is nothing more than a program designed to share information with another program. It has an .EXE file extension.

ActiveX DLL: ActiveX DLL files are not meant to be used by themselves. Instead, these types of files contain subprograms designed to function as building blocks when creating a stand-alone program. It has a .DLL file extension.

ActiveX Control: Unlike an ActiveX DLL or ActiveX EXE file, an ActiveX Control file usually provides both subprograms and a user interface that you can reuse in other programs. It has an .OCX file extension.

1. The ActiveX EXE/DLL is normally used when you need to build a component that is separate from the main program. The concept is based on COM model.

2. ActiveX DLL/EXE allows multiple applications to share the same code. This allows for scalability of programs, and saves time because you only need to write the code once.

3. ActiveX DLLs and ActiveX EXEs are almost same in the ways they are built and used. In either case, you build one or more classes that applications can use to do something.

4. One of the main differences between ActiveX EXE and an ActiveX DLL's is that the code is executed within the main program's address space for ActiveX DLL. This is because the code lies inside the program's address space, calling methods and execution of code is very fast.


An ActiveX Exe provides the reusability of code, by accessing it from different clients.

An ActiveX Exe is a component that can be called by another application by providing a reference to the component. But a Standard Exe application cannot be called in this way.

An ActiveX EXE's code is run in a separate process. When the main program calls an ActiveX EXE's method, the application passes required parameters into the ActiveX EXE's and calls the method. The ActiveX EXE, upon execution may return the results to the main program. This is slower than running an ActiveX DLL's method inside the main program's address space.

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