You will learn how to implement different security mechanisms for your Web application in Chapter 25.
Deploying ASP.NET Applications
You can deploy ASP.NET applications by copying the files in the virtual directory of an application to a virtual directory on the destination server. However, Visual Studio .NET provides a more sophisticated method of deployment. Instead of manually copying all ASP.NET files, you can use the Web Setup deployment project in Visual Studio .NET.
The Web Setup deployment project is a project template that can be configured to accomplish the necessary tasks to deploy a Web application. Some tasks that you can configure using the Web Setup project template are specified in the following list:
Check for the presence of .NET run-time files and other prerequisite software before installing the application.
Prompt the user for the name for the virtual directory in which the application should be installed.
Enforce business rules, such as acceptance of user agreements, before the installation of the software.
Create databases and add data that might be necessary for the successful execution of your application.
It is advisable to use the Web Setup project template for deploying your ASP.NET applications. However, another easy method to deploy your application is to use the Copy Project feature in Visual Studio .NET. This feature copies the source files of the application to a virtual directory that you specify. You can use this feature only when the computer on which you want to deploy your application is accessible on the network. It is not possible to use it to distribute your application to customers or business partners. I will describe the steps to deploy ASP.NET applications in Chapter 26, “Deploying the Application.”
Creating a Sample ASP.NET Application
After having examined the basic concepts of an ASP.NET application, you can build on your knowledge by attempting a simple ASP.NET application. In this
444 Project 4 CREATING AN AIRLINE RESERVATION PORTAL
section, I have created a simple application that queries a username and password in a database and displays a welcome message if the user is successfully authenticated.
Creating a New Project
The first step in creating an ASP.NET application in Visual Studio .NET is to add a new project by using the ASP.NET Web Application template. The steps to add a new ASP.NET Web Application were discussed in the section “Summary of Web Form Server Controls.” Create a new project with the name SampleApplication. After creating the new project, proceed to the next section, “Adding Controls to the Project,” to add controls to the sample application.
Adding Controls to the Project
To design the user interface of the application, you need to add controls to the application. The steps to add controls to the Web form are specified in the following list:
1.Click on the View menu and select Toolbox to open Toolbox.
2.Drag a Label control from Toolbox to the default form in the Web application.
3.Change the properties of the label as given here:
ID=lblCaption
Text=Please log on
Font
Bold=True
Italic=True
Name=Georgia
4.Drag two label controls to the form for accepting the username and the password. Change the Text property of these label controls to User Name and Password, respectively.
5.Drag two TextBox controls to the form and change their ID to txtUserName and txtPassword, respectively.
6.Drag a Button control to the form and change its Text property to Submit. In addition, change the ID of the button to btnSubmit.
BASICS OF ASP.NET WEB APPLICATIONS
Chapter 19
445
The basic structure of the form is complete. Next, you need to add validation controls to the form to validate user input before data is processed on the server. To add validation controls to the form, follow these steps:
1.Drag a RequiredFieldValidator control to the form for validating the User Name text box. Change the properties of the RequiredFieldValidator control as mentioned in the following list:
ErrorMessage=Invalid user name
ControlToValidate=txtUserName
2.Drag another RequiredFieldValidator control to the form for validating
the Password text box. Change the properties of the control as mentioned here:
ErrorMessage=Invalid password
ControlToValidate=txtPassword
The interface of the form is complete. However, you can add one more Label control to display a welcome message if the user logs on successfully. Change the ID of the label to lblMessage and clear the Text property. The complete form is shown in Figure 19-3.
FIGURE 19-3Form to accept username and password
After having designed the interface of the form, you can code the functionality of the Web application.
446 Project 4 CREATING AN AIRLINE RESERVATION PORTAL
Coding the Application
To code the functionality of the application, you need to create the database structure and use the database to validate users. In this section, I will explain the procedure for creating a database and utilizing it in the application.
Creating the Database
To validate the username and the password, I have created a database named SampleDatabase and added a Logon table to the database. Next, I added two records to the Logon table. To create a similar structure for your Web application, execute the SQL script given as follows:
CREATE DATABASE SampleDatabase
GO
USE SampleDatabase
GO
CREATE TABLE Logon (
[UserName] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL , [Password] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL
) ON [PRIMARY] GO
ALTER TABLE Logon WITH NOCHECK ADD
CONSTRAINT [PK_Logon] PRIMARY KEY CLUSTERED
(
[UserName] ) ON [PRIMARY]
GO
INSERT INTO LOGON
VALUES (‘John’, ‘password’)
GO
INSERT INTO LOGON
VALUES (‘Suzan’, ‘mypassword’)
GO
Adding Functionality to the Application
ASP.NET includes data access tools that make it easier for you to interact with databases. The SQL Server .NET data provider is used for accessing SQL Server databases. The data provider provides three primary classes to access databases:
BASICS OF ASP.NET WEB APPLICATIONS
Chapter 19
447
SqlConnection. The SqlConnection class is used for creating a connection to the database.
SqlDataAdapter. The SqlDataAdapter class is used for adding, updating, deleting, and selecting records from the database.
DataSet. The DataSet class is used to cache data that is retrieved from a database. A DataSet object comprises a number of DataTable objects that contain data retrieved from database tables.
In addition to the three classes described here, ASP.NETprovides the SqlCommand class that can be used for executing queries on a database.
Visual Studio .NET provides data controls that correspond to the SQL Server data provide classes described in the previous list. These controls are available on the Data tab of the Toolbox. Follow these steps to use the data controls for accessing databases:
1.Drag an SqlDataAdapter control from Toolbox to the form. Data Adapter Configuration Wizard will start.
2.On the Welcome screen, click on Next. The Choose Your Data Connection screen of the wizard will appear.
3.On the Choose Your Data Connection screen, click on New Connection. The Data Link Properties dialog box will appear, as shown in Figure 19-4.
FIGURE 19-4The Data Link Properties dialog box
448 Project 4 CREATING AN AIRLINE RESERVATION PORTAL
4. In the Data Link Properties dialog box, configure the connection to the database that you created in the previous section and click on OK. The data connection that you created will be displayed on the Choose Your Data Connection screen of the Data Adapter Configuration wizard.
5. Click on Next. The Choose Query Type screen will appear.
6.
On the Choose Quer y Type screen, retain the default option and click
on Next. The Generate the SQL Statements screen will appear.
7.
Specify the SQL Query as specified and click on Next.
F
Select UserName, Password from
ogon where (UserName=@username)
8.
M
On the View Wizard results screen,Yclick on Finish to complete the
wizard.
A
L
When you complete the wizard, new SqlDataAdapter and SqlConnection con-
E
trols are added to your project.These controls appear in Component Designer, as
T
shown in Figure 19-5.
FIGURE 19-5Adding new SqlDataAdapter and SqlConnection controls to the form
In the preceding steps, you used the Data Adapter Configuration wizard to configure the SqlDataAdapter and SqlConnection controls. However, Visual Studio
.NET offers another simple mechanism to configure these controls without traversing the wizard. This method is specified below:
Team-Fly®
BASICS OF ASP.NET WEB APPLICATIONS
Chapter 19
449
1.Click on the View menu and select Server Explorer to open the Server Explorer window.
2.In the Server Explorer window, navigate to the table for which you want to configure the data adapter. For example, the path to the Logon table is shown in Figure 19-6.
3.Press and hold the mouse button on the name of the table and drag it to the form. Visual Studio .NET will automatically add the SqlDataAdapter and SqlConnection controls to your form.
FIGURE 19-6Using the Server Explorer to add data cont rols
In the SkyShark Airlines project, I will use Server Explorer to configure the connections to database tables.
After adding data controls to the Web form, you need to add a DataSet control to the form. To add the DataSet control to the form, perform the following steps:
1.Click on the Data menu and then click on Generate Dataset. The Generate Dataset dialog box will appear, as shown in Figure 19-7.
2.Click on OK to configure a new DataSet control and add it to Component Designer.
450 Project 4 CREATING AN AIRLINE RESERVATION PORTAL
FIGURE 19-7Adding a new DataSet cont rol
You have added all the required controls to configure your application. In the last step, add the following code for the Click event of the Submit button:
In the preceding code, the following sequence of tasks is performed:
1.The connection to the database is opened by the Open function.
2.The value specified by the user for the username is assigned to the first parameter of the SELECT query. The first parameter is @username.
3.The Fill method of the SqlDataAdapter class is used for executing the select query and adding the resultant data to the data set. The Fill command accepts two parameters, the name of the data set and the name of the DataTable in the data set in which the data should be stored.
4.If the number of rows returned by the select command is 0 as determined by the Count property of the Rows collection of a DataTable, an error message is displayed to the user.
5.If the number of rows returned is greater than 0, the password specified by the user is validated against the password retrieved from the database. The password retrieved from the database is stored in the second column of the first row of a DataSet table and can be accessed at the position Rows[0][1].
TIP
The first member of a collection has the index 0.Therefore, to access the second element, which is the password in this case, the index that needs to be used is 1.
6.If the password specified by the user matches the password retrieved from the database, a welcome message is displayed. If the password does not match, an error message is displayed.
After specifying the preceding code, click on Debug and then Start to run the application. The output of the application, which is generated after you specify a valid username and password, is shown in Figure 19-8.
