Structures: Your Own Data Types

A structure is a generalization of the user-defined type (UDT) supported by previous versions of Visual Basic. In addition to fields, structures can expose properties, methods, and events. A structure can implement one or more interfaces, and you can declare individual access levels for each field.

You can combine data items of different types to create a structure. A structure associates one or more elements with each other and with the structure itself. When you declare a structure, it becomes a composite data type, and you can declare variables of that type.

Structures are useful when you want a single variable to hold several related pieces of information. For example, you might want to keep an employee's name, telephone extension, and salary together. You could use several variables for this information, or you could define a structure and use it for a single employee variable. The advantage of the structure becomes apparent when you have many employees and therefore many instances of the variable.

In This Section

• How to: Declare a Structure
  Shows how to declare a structure and its elements.

• Structure Variables
  Covers assigning a structure to a variable and accessing its elements.

• Structures and Other Programming Elements
  Summarizes how structures interact with arrays, objects, procedures, and each other.

• Structures and Classes
  Describes the similarities and differences between structures and classes.

Related Sections

• Data Types in Visual Basic
  Introduces the Visual Basic data types and describes how to use them.

• Data Type Summary (Visual Basic)
  Lists the elementary data types supplied by Visual Basic.