A structure is a user defined type, which is used to hold multiple types of related data and is a generalization of a user defined data type (UDT). In other words, we combine variables of different data types to create a structure and use them when we do not want the additional functionality of an extendable class and when it will not contain large amount of a data. These are a replacement of UDT in visual basic 6.0. Compared to UDTs these are easier to implement. We can create one, when we want a single variable to hold multiple types of related data. In visual basic 2005, we can one using 'Structure-and-End-Structure' statements. The members are declared in between the 'Structure-and-End-Structure' statements. For example, we can maintain Stock details in a single variable, we can do it as follows:
Public Inv_No as String
Public Inv_Date as Date
Public ItemName as String
Public Qty as Integer
The variables declared are called data members. The access modifiers that we can use and the Access Scope
defined by each access modifier are listed below.
Declared with the Public keyword is accessible from anywhere within or outside the application. This is the default access mode.
Declared with the Friend keyword is accessible from within the program that contains its declaration and from anywhere else in the same program.
Declared with the Private keyword is accessible only from within its declaration context, including any nested procedures.
Declared with the Protected keyword is accessible only from within its own class or from a derived class.
- Protected Friend
Declared with the Protected Friend keyword is accessible from within the same assembly and in the derived classes.
We can also include procedures as members. For example, if you want to include a procedure to check the value entered for the stock variable, we can define it as shown below:
Public Inv_No As String
Public Inv_Date As Date
Public ItemName As String
Public Qty As Integer
Public Sub CheckQty(BYVal Qty As Integer)
If Qty < 10 Then
After we declare, we can create the objects. The objects enables us to access the members by using the dot notation.
Dim inv1 As stock_details
In the above example, inv1 is a type variable and Inv_No, Inv_Date, ItemName and Qty are the members of the type variable.
You can access a member variable to validate the data stores in the members in the following manner:
If inv1.InvNo= " " Then
MsgBox ("Please enter the Invoice Number")
In this article we have seen how to create, store data and access data from a structure.
Develop Azure Applications
Azure Cloud is gaining popularity and is competing with Amazon Elastic Cloud and Google Cloud for a spot in the billion dollar Cloud computing space.
With this book learn how to use - Table (an Azure Table is different from a SQL Server Table), Queue, Blob storage services, use your local machine to create an Application and a Service, how Azure splits a Table to achieve Load Balancing, Scalability based on the Partition Key, AppFabric Service Bus, Access Control Service, role of Fabric Controller, features of Azure SQL Database and Content Delivery Network.
Many have mastered Cloud Programming and are enjoying the benefits. Why not you?
Create your Own Accounting Software
A foundation book to Master Accounting Software Development, VB.Net, C# and OOPs programming. Detailed explanation of the Accounting domain for programmers is included. SQL and ADO.Net is also covered in detail.
This book gives you a strong foundation in Application Development.
A thorough understanding of the contents will enable you to grasp the topics covered in the accompanying books quite easily. This is because, the accounting domain is dealt with great detail in this book.
The ideal book to get started with application development in the .Net world.
Create your Own WEB ERP Software using ASP.Net
This book opens you to the Web. Using ASP.Net, C# and SQL Server as the tools, you will learn to build a Multi Tier Web Application as recommended by Microsoft. You will learn implementing inline GridView control, Transaction Management for a layered Web Application, build Data Access component and a Business Layer component.
Opens you to a world of opportunities. You will be able to develop a Web ERP application including all the five modules and learn how to use the TreeView control and GridView control to implement transactions such as Purchase Invoice, Sales Order and Sales Invoice.
ASP.Net MVC 5 Application Development Using Entity Framework 6 and VS 2015
Entity frameworks is the latest buzz in .Net programming and is the data access technology for Microsoft OS based hand held devices and web applications. Learn to integrate EF into an ASP.Net Application and MVC application. Create, explore and query the Entity Data Model. Learn how to use ObjectDataSource control and GridView control in an ASP.Net Application.
Also, learn to build Three-Tier ASP.Net application, create a business-class, implement methods in the class to perform CRUD operations and bind a GridView to the ObjectDataSource control. Learn how to handle concurrency and managing Transactions.