The Structure of a Visual Basic Application
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An application is really nothing more than a set of instructions directing the computer to perform a task or tasks. The structure of an application is the way in which the instructions are organized; that is, where the instructions are stored and the order in which instructions are executed.
Forms
The first step to creating an application with Visual Basic is to create the interface, the visual part of the application with which the user will interact. Forms and controls are the basic building blocks used to create the interface; they are the objects that you will work with to build your application.
Forms are objects that expose properties which define their appearance, methods which define their behavior, and events which define their interaction with the user. By setting the properties of the form and writing Visual Basic code to respond to its events, you customize the object to meet the requirements of your application.
Form Module
For each form in an application, there is a related form module (with file name extension .frm) that contains its code.Each form module contains event procedures.
Standard Module
Code that isn't related to a specific form or control can be placed in a different type of module, a standard module (.BAS). A procedure that might be used in response to events in several different objects should be placed in a standard module, rather than duplicating the code in the event procedures for each object.
Class Module
A class module (.CLS) is used to create objects that can be called from procedures within your application. Whereas a standard module contains only code, a class module contains both code and data — you can think of it as a control without a physical representation.
Controls
Controls are objects that are contained within form objects. Each type of control has its own set of properties, methods and events that make it suitable for a particular purpose. Some of the controls you can use in your applications are best suited for entering or displaying text. Other controls let you access other applications and process data as if the remote application was part of your code.
Properties, Methods and Events
Visual Basic forms and controls are objects which expose their own properties, methods and events. Properties can be thought of as an object's attributes, methods as its actions, and events as its responses.
<< Back to Index
An application is really nothing more than a set of instructions directing the computer to perform a task or tasks. The structure of an application is the way in which the instructions are organized; that is, where the instructions are stored and the order in which instructions are executed.
Forms
The first step to creating an application with Visual Basic is to create the interface, the visual part of the application with which the user will interact. Forms and controls are the basic building blocks used to create the interface; they are the objects that you will work with to build your application.
Forms are objects that expose properties which define their appearance, methods which define their behavior, and events which define their interaction with the user. By setting the properties of the form and writing Visual Basic code to respond to its events, you customize the object to meet the requirements of your application.
Form Module
For each form in an application, there is a related form module (with file name extension .frm) that contains its code.Each form module contains event procedures.
Standard Module
Code that isn't related to a specific form or control can be placed in a different type of module, a standard module (.BAS). A procedure that might be used in response to events in several different objects should be placed in a standard module, rather than duplicating the code in the event procedures for each object.
Class Module
A class module (.CLS) is used to create objects that can be called from procedures within your application. Whereas a standard module contains only code, a class module contains both code and data — you can think of it as a control without a physical representation.
Controls
Controls are objects that are contained within form objects. Each type of control has its own set of properties, methods and events that make it suitable for a particular purpose. Some of the controls you can use in your applications are best suited for entering or displaying text. Other controls let you access other applications and process data as if the remote application was part of your code.
Properties, Methods and Events
Visual Basic forms and controls are objects which expose their own properties, methods and events. Properties can be thought of as an object's attributes, methods as its actions, and events as its responses.
