Build Step by Step a Complete Database App. in VB .Net

Dear Student's welcome to my main course.

In this course we will build step by step an application which will have access to a database consisting of Customers placing Orders and Performing transactions.

I will try to put my best effort so that you understand intermediary concepts in ASP.NET.

This is an intermediary level course so i presume that you have a basic knowledge of Visual Basic Programming and Visual Studio tools in general.

In this lecture you will be able to see the structure of the Customers-Orders web application.

You will explore the first web page of the program which is the default.aspx page (and is the startup page when the application begins

in run mode).

I will describe the basic components that  the page is consisted together with the source code behind the form.

By the end of these lectures i believe that you will be able to have a very good knowledge of  ASP.NET programming

So let us start !

The default page is the start page of the application.

It consist of a main menu where the user can navigate through the application.

There is also an AdRotator tool which has 4 images that change every few seconds via a Timer component and at the bottom

of the page there is a label which shows the user name who is log in and a button for logging out of the application.

I also included a link text which prompts the user to read some instructions of the program. 

The following lecture describes the new technology that Microsoft uses since 2002 and it is called ADO.NET

ADO.NET (ActiveX Data Objects.NET) is the primary data access API for the .NET framework.

It provides the classes that you use as you develop database applications in Visual Basic and other .NET languages.

One way to develop database applications with ADO.NET is to use the datasets. With the following approach, your application gets data from a database (in our example we used MS Access), and stores it in a dataset. The dataset is kept in cache memory on disk. Then by using the application you can add, update, delete rows in the dataset and it can later save those changes from the dataset to the database.

With this approach your application uses the ADO.NET objects. To load data into the data table within the dataset you need to use the data adapter. Its main function is to manage the flow of data between the dataset and the database. To do that the data adapter uses commands that define the SQL statements to be issued. The command that retrieves data is the SELECT statement, and the command that update a record in the dataset is the UPDATE statement. After the issuing of the SELECT statement, the command connects to the database using a connection and passes the SELECT statement to the database. After the SELECT statement is executed the result set it produces is sent back to the data adapter, which stores the result in the data table.

To update the data in the database, the data adapter determines which rows in the data table have been inserted, updated or deleted. Then it uses commands that define those statements as SQL instructions for the data table to update the associated rows in the database. Again in order to execute those statements, a connection must be issued to the database.

An important thing to note is that the data in the dataset is independent from the database that the data was retrieved from. In fact the connection to the database is closed after the data is retrieved from the database. Then the connection is opened again when needed. In few words, the application must work with a copy of the data which is stored in the dataset.

The architecture that is used to implement this type of data processing is called disconnected data architecture. Although this approach is more complicated than the previous technology, it has several advantages. The main advantage is that using disconnected data architecture can improve system performance due to the use of fewer system resources for maintaining several connections.

Please open the attached documentation which describes each command in detail and the flow of data between the program and the actual database.

In this lecture we are going to analyze the Customers web page.

We will describe the various components that the Customers page consists off such as the datagrid component that all the customer's off the database are show.

There is a Total Visitors label and a textbox which shows the number of visitors in the Customers page(which is also available for anonymous users).

The Add New Customer web button is for insert a new customer in the CustomersOrders database.

I have included field validator code which you will see next in the Visual Basic code of the page.

There is also the SiteMapDataSource component which displays the Navigation path of the page.

Finally when you click in the view orders link you will be prompted to Log In in order to view the Orders page because both Orders and Transactions web pages are for register users.

All these components are supported by programming code which is available to you and well explained so that you understand the functionality of the page.

This lecture will demonstrate the Orders and the Transactions web pages which are only accessible to registereind users.

Registered users are the users who singed up in the program and have a user name and user password.

The Orders page is the page that a specific customer in our database will place an order.

In this page we can see all the pending order's by a customer and there is the option to select a particular order from the datagrid  (that will appear in a form view) and we can settle or pay part of the order by entering an amount  and press the Payment button.

Also in this page there are text fields with validator code, to add a new order.

There is also a link text that when you click on it will redirect you to the Transactions page and a SiteMapDataSource which shows in a tree structure the navigation path (as the component name implies!)

Finally the Transactions page is rather simple.  That page has a databound list control which you select the order number and you see all the transactions that a specific order has.

In this lecture we will discuss the ASP.NET Roles and  Membership.

When we are working on applications where authentication and authorization is a key requirement, then we will find the ASP.NET roles and membership feature very useful. Authentication means validating users. In this step, we verify user credentials to check whether the person tying to log in is the right one or not. Authorization on the other hand is keeping track of what the current user is allowed to see and what should be hidden from him. It is more like keeping a register to what to show and what not to show to the user.

Whenever a user logs in, he will have to authenticate himself with his credentials. Once he is authenticated, he will be authorized to see resources/pages of the website. Mostly these two concepts go together and ASP.NET provides us with some server controls that provide a lot of functionality.

If we use ASP.NET's authentication and authorization mechanism, then we can focus on what should be authorized and who should be authenticated.

In our Application which i  have programmed with Visual Studio 2012 the ASP Web Site Administration Tool was in the main menu to select and start running the wizard by selecting roles for the user's.

From Visual Studio 2013 and later versions though, there is a procedure that must be followed for accessing this tool.

I have found a good article which you can read so that to have access to this tool with newer versions.

https://www.c-sharpcorner.com/UploadFile/4b0136/working-with-Asp-Net-identity-in-empty-project-in-visual-stu/

Finally we will describe the Web. config tool which is essential in our project

Dear Students,

We have completed the description of the Web Application and i hope that by now  you are in position to understand the application how it works.

I have sent you a video content describing the application in design view and in run mode and you will also find the actual project in a .zip file.

Please Unzip the file, open the folder and find the solution file (Customers.sln). if you double click the file the project will open in design view in Visual Studio 2017.

I hope you liked my course and find the application interesting. 

P.S : Remember in order to login as administrator the username is : Marios  and Password is %alfapizza !

Dear Student's

This last "lecture" is a description of a database program i have made few years back. It is very similar to the database program i have presented in ASP. Net but this one is made in VB .Net 2012 and upgraded to VB. Net 2017.

Read the readme.doc file in the resources to see what it does. I am sure you will appreciate it. It is a complete application for Stock Control and as my previous programs every part of the code is very well explained.

So Enjoy !

In this lecture we are going to speak about creating and printing a report i.e Customer's report.

In order to achieve this we need a Listview control.

The ListView control is used to display a list of items. Along with the TreeView control, it allows you to create a Windows Explorer like interface.

The ListView control displays a list of items. The Item property of the ListView control allows you to add and remove items from it. The SelectedItem property contains a collection of the selected items. The MultiSelect property allows you to set select more than one item in the list view. The CheckBoxes property allows you to set check boxes next to the items.

There are many properties and methods of the Listview control which you are going to see in the coding example i will present to you.

You can view all these properties, methods and events of the Listview control by a quick look in the internet.

Finally we are going to speak about printing the report. We will need 3 objects to achieve this.

We will drag on the form the Printpreviewdialog tool, the PageSetupdialog tool and the Printdocument tool.

Please watch the video lecture carefully in order to understand hoe it all fit together.