Top ActiveX Interview Questions & Answers:
1. Explain object serialization?
A serialized object represents the type of data stored in the object, its information. Object serialization is a process of reading or writing an entire object from a file. This helps in saving session state information by servlets, for sending parameters for Remote Method Invocation (RMI) calls.
Globally Unique Identifier - A 16-byte number generated by Microsoft programs that uniquely identifies a network or user or computer or document. It is one of the elements of information that can be passed when you connect to an Internet site, and it may be stored in cookies
A globally unique identifier (GUID) is used for unique IDs. No two GUIDs are the same no matter what computer they were generated on. The attribute clsid defines the GUID of the associated ActiveX control to use.
3. How COM provide the language transparency?
COM defines an API to allow for the creation of components for use in integrating custom applications or to allow diverse components to interact.
But in order to interact, components must adhere to a binary structure specified by Microsoft.
As long as components adhere to this binary structure, components written in different languages can interoperate.
4. Explain about type library?
A file or component within another file that contains standard descriptions of exposed objects, properties, and methods
A type library contains a binary description of an interface exposed by a COM-component. In this sense, they contain the same information that is contained in an IDL (Interface Definition Language) file.
5. Explain what is Component Object Model?
COM defines an API to allow for the creation of components for use in integrating custom applications or to allow diverse components to interact.
But in order to interact, components must adhere to a binary structure specified by Microsoft.
As long as components adhere to this binary structure, components written in different languages can interoperate.
6. Explain what is IUnknown interface?
IUnknown interface provides clients like DirectX control of to get pointers to other interfaces. All COM interfaces are inherited from IUnknown interface. It is used In multiple inheritance where the various interfaces can share one implementation of IUnknown.
Object Linking and Embedding (OLE) is about using documents generated by one application inside another application.
ActiveX is a Microsoft rebranding of OLE with more focus on smart Windows controls.
8. Define shallow and deep copy?
A shallow copy just copies the values of the data as they are. Even if there is a pointer that points to dynamically allocated memory, the pointer in the copy will point to the same dynamically allocated.
9. Explain STL, standard template library?
STL contains classes, algorithms, and iterators. It contains set of ready to use C++ classes that can be used with built in type and user defined operations. STL uses templates to achieve the results.
10. What are some other development tools that support creating and using ActiveX controls?
1. MFC
2. ATL
3. C++
4. VB
through Visual Studio.
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