Answer: – Classes are the building blocks of an object-oriented application. A class is a programming construct that represents an object in the system. Designing an application requires designing the objects involved, the information contained by the objects, and what the objects can do. For more information on classes and object-oriented programming, see object-oriented programming in visual basic. Visual basic 6.0 provides support for defining classes through the class module. The definition of a class is stored in a special file type, the .cls file. One class is defined in each class module. Some of the definition of the class is embedded in the .cls file and only editable through the project system.
An object is a combination of code and data that can be treated as a unit. An object can be a piece of an application, like a control or a form. An entire application can also be an object.
When you create an application is visual basic, you constantly work with objects. You can use objects provided by visual basic, such as controls, forms, and data access objects you can also use objects from other applications within your visual basic application. You can even create your own objects and define additional properties and methods for them. Objects act like prefabricated building blocks for programs – they let you write a piece of code once and reuse it over and over.
Each object in visual basic is defined by a class. A class describes the variables, properties, procedures, and events of an object. Objects are instances of classes; you can create as many objects you need once you have defined a class.
To understand the relationship between an object and its class, think of cookies cutters and cookies. The cookies cutter is the class. It defines the characteristics of each cookie. For example, size and shape. The class is used to create objects. The objects are being cookies.
You must create an object before you can access its members.
Object linking and embedding (OLE, sometimes pronounced) is a proprietary technology developed by Microsoft that allows embedding and linking to documents and other objects. For developers, it brought OLE control extension (OCX), a way to develop and use custom user interface elements. On a technical level, an OLE object is any object that implements the IOleObject interface, possibly along with a wide range of other interfaces, depending on the object’s needs.