Build Your Own ASP.NET Website Using C# & VB.NET

.NET is the result of a complete make-over of Microsoft’s software development products, and forms part of the company’s new strategy for delivering software as a service. The key features that .NET offers include:

The book focuses on one of the core components within the .NET Framework: ASP.NET.

For years now, Active Server Pages (ASP) has been arguably the leading choice for Web developers building dynamic Websites on Windows Web servers. ASP has gained popularity by offering the simplicity of flexible scripting via several languages. That, combined with the fact that it’s built into every Microsoft Windows-based Web server, has made ASP a difficult act to follow.

Early in 2002, Microsoft released its new technology for Internet development. Originally called ASP+, it was finally released as ASP.NET, and represents a leap forward from ASP both in sophistication and productivity for the developer. It continues to offer flexibility in terms of the languages it supports, but instead of a range of simple scripting languages, developers can now choose between several fully-fledged programming languages. Development in ASP.NET requires not only an understanding of HTML and Web design, but also a firm grasp of the concepts of object-oriented programming and development.

In the next few sections, I’ll introduce you to the basics of ASP.NET. I’ll walk you through installing it on your Web server, and take you through a simple dynamic example that demonstrates how ASP.NET pages are constructed. First, let’s define what ASP.NET actually is.

ASP.NET is a server-side technology for developing Web applications based on the Microsoft .NET Framework. Let’s break that jargon-filled sentence down.

ASP.NET is server-side; that is, it runs on the Web server. Most Web designers start by learning client-side technologies like HTML, JavaScript, and Cascading Style Sheets (CSS). When a Web browser requests a Web page created with client-side technologies, the Web server simply grabs the files that the browser (the client) requests and sends them down the line. The client is entirely responsible for reading the code in the files and interpreting it to display the page on the screen. Server-side technologies, like ASP.NET, are different. Instead of being interpreted by the client, server-side code (for example, the code in an ASP.NET page) is interpreted by the Web server. In the case of ASP.NET, the code in the page is read by the server and used dynamically to generate standard HTML/JavaScript/CSS that is then sent to the browser. As all processing of ASP.NET code occurs on the server, it’s called a server-side technology. As Figure 1.1 shows, the user (client) only sees the HTML, JavaScript, and CSS within the browser. The server (and server-side technology) is entirely responsible for processing the dynamic portions of the page.

Figure 1.1. The Web server is responsible for processing the server-side code and presenting the output to the user (client).

ASP.NET is a technology for developing Web applications. A Web application is just a fancy name for a dynamic Website. Web applications usually (but not always) store information in a database on the Web server, and allow visitors to the site to access and change that information. Many different programming technologies and supported languages have been developed to create Web applications; PHP, JSP (using Java), CGI (using Perl), and ColdFusion (using CFML) are just a few of the more popular ones. Rather than tying you to a specific technology and language, however, ASP.NET lets you write Web applications using a variety of familiar programming languages.

Finally, ASP.NET is based on the Microsoft .NET Framework. The .NET Framework collects all the technologies needed for building Windows applications, Web applications, and Web Services into a single package with a set of more than twenty programming languages. To develop Websites with ASP.NET, you’ll need to download the .NET Framework Software Development Kit, which I’ll guide you through in the next few sections.

Even with all the jargon demystified, you’re probably still wondering: what makes ASP.NET so good? Compared with other options for building Web applications, ASP.NET has the following advantages:

With all these advantages, ASP.NET has relatively few downsides. In fact, only two come to mind:

Still with me? Great! It’s time to gather the tools and start building!

For the moment, if you’re going to learn ASP.NET, you’ll need a Windows-based Web server. Open source initiatives are underway to produce versions of ASP.NET that will run on other operating systems, such as Linux; however, these are not expected to be available in stable form for a while.

While developers had the option of getting their feet wet with ASP on Windows 95, 98, or ME, using a scaled-down version of IIS called a Personal Web Server (PWS), ASP.NET requires the real deal. As a bare minimum, you’ll need a computer equipped with Windows 2000 Professional before you can get started. Windows XP Professional will work fine too, as will any of the Windows 2000 Server packages and Windows 2003 Server.

Other than that, all you need is enough disk space to install the Web server Internet Information Services (18 MB), the .NET Framework SDK (which includes ASP.NET; 108 MB), and a text editor. Notepad or Web Matrix will be fine for getting started, and are certainly all you’ll need for this book. However, if you get serious about ASP.NET, you’ll probably want to invest in a development environment like Visual Studio .NET.

This section tackles the necessary installation and configuration of software that you’ll need for this book, including:

We’re also going to need a database. In this book, we’ll use:

Or alternatively, you might use:

Configuring IIS

Although little configuration needs to be done before you begin working with IIS, I’ll use this section to introduce some basic features and functionality within IIS:

• Determining whether ASP.NET installed correctly

• Determining where files are located on the Web server

• Using localhost

• How to start and stop the Web server

• How to create a new virtual directory and modify its properties

Determining whether ASP.NET Installed Correctly

Once IIS is installed on your computer, you can open it by selecting Internet Information Services from the Administrative Tools menu. The first task is to make sure that ASP.NET was integrated into IIS when you installed the .NET Framework. Although, logically, ASP.NET should install automatically because it’s a component of the .NET Framework, sometimes it doesn’t. Don’t let this alarm you—it’s a common occurrence and is addressed in the Microsoft Knowledge Base. You can determine whether IIS was installed correctly by following these steps:

1. Open IIS, if you haven’t already done so, and click on the + symbol next to your computer’s name.

2. Right-click Default Web Site and select Properties.

3. Navigate to the Documents tab. If default.aspx appears within the list, ASP.NET was installed correctly.

Another way to check whether ASP.NET installed correctly is by following these steps:

1. Navigate to the Application Mappings menu by right-clicking the root Website node (your computer’s name) and choosing Properties.

2. Select the Home Directory tab, and choose Configuration.

3. The Application Mappings menu displays all of the extensions and their associated ISAPI Extension DLLs, as we see in Figure 1.2.

Figure 1.2. If the .aspx ISAPI Extension DLL appears within the Application Mappings menu, then ASP.NET was installed correctly.

Since I can imagine you’re dying to know what an ISAPI Extension DLL is, let me explain. You may know that a DLL is a Dynamically Linked Library, which is essentially a self-contained code module that any number of applications can draw on. When a Web server hosts a dynamic Website, page requests must be processed by program code running on the server before the resultant HTML can be sent back to the requesting browser (the client). Now, as was the case with traditional ASP, ASP.NET performs this processing with the help of its Internet Server Application Programming Interface (ISAPI) extension DLL. ISAPI allows Web requests to be processed through the Web server by a DLL, rather than an EXE, as is the case with Common Gateway Interface (CGI) pages. This approach is advantageous because DLLs are much more efficient, and require far less resources and memory than executables. IIS uses the file extension of a requested page to determine which DLL should process the request according to the mappings shown in the screenshot above. So, we can see that pages ending in .aspx, .asmx, or .ascx, among others, will now be passed by IIS to the ASP.NET DLL (aspnet_isapi.dll) for processing. OK, enough of the tech-talk. Let’s get back to it!

If you’ve come to the conclusion that ASP.NET was not installed on your computer, you’ll have to install it manually from the command prompt:

1. Open the command prompt by selecting Start > Run, type CMD, and select OK.

2. Type the following command (all on one line) to install ASP.NET on Windows 2000 Professional, Server, or Advanced Server:

   C:\WINNT\Microsoft.NET\Framework\ver\aspnet_regiis.exe -i

   Or on Windows XP Professional:

   C:\WINDOWS\Microsoft.NET\Framework\ver\aspnet_regiis.exe -i

   In these commands, ver is the directory corresponding to the version of the .NET Framework you have installed.

3. Once ASP.NET is installed, close the command prompt and check again to confirm whether ASP.NET installed correctly.

If it still hasn’t installed, try visiting the Microsoft Knowledge Base for help.

Where Do I Put My Files?

Now that you have ASP.NET up and running, let’s take a look at where the files for your Web applications are kept on the computer. You can readily set IIS to look for Web applications within any folder of your choice, including the My Documents folder or even a network share. By default, IIS maps the wwwroot subfolder of C:\Inetpub on the server to your Website’s root directory, and it is generally considered a good repository for storing and managing your Web applications.

If you open this wwwroot folder in Windows Explorer, and compare it with the folder tree that appears on the left of the IIS console, you’ll notice that the folders in Explorer also appear under your Default Web Site node. Note that, while several of these folders have the regular Explorer folder icon in the IIS view, others have a special Web application icon, indicating that these folders contain the pages and other items for a particular Web application. These special folders are what IIS calls Virtual Directories, and, in fact, they do not have to share the name of the physical folder to which they map. We’ll see more on this shortly.

Using Localhost

By putting your files within C:\Inetpub\wwwroot, you’ve given your Web server access to them. If you’ve been developing Web pages for a long time, habit may drive you to open files directly in your browser by double-clicking on the HTML files. Because ASP.NET is a server-side language, your Web server needs to have a crack at the file before it’s sent to your browser for display. If the server doesn’t get this opportunity, the ASP.NET code is not converted into HTML that your browser can understand. For this reason, ASP.NET files can’t be opened directly from Windows Explorer.

Instead, you need to open them in your browser using the special Web address that indicates the current computer, http://localhost/. If you try this now, IIS will open up some HTML help documentation, because we’ve not yet set up a default Website. This localhost name is, in fact, equivalent to the so-called loopback IP address, 127.0.0.1, IP which you can check out by entering http://127.0.0.1/ in your browser; you should see the same page you saw using localhost. If you know them, you can also use the name of your server or the real IP address of your machine to the same effect.

Note that if you do try any of these equivalents, a dialog will appear before the page is opened, asking for your network credentials, because you’re no longer using your local authentication implicit with localhost.

Stopping and Starting IIS

Now that we have IIS up and running, and ASP.NET installed, let’s look at how you can start, stop, and restart IIS if the need arises. For the most part, you’ll always want to have IIS running, except when you’re using certain programs locally that open ports and allow intruders to compromise the security of your computer. Some programs, like Kazaa, automatically stop IIS upon launch, because of potential security vulnerabilities. If you want to stop IIS when it’s not being used, simply follow the steps outlined below:

1. With IIS open, select Default Web Site. The Play, Stop, and Pause icons will become visible.

2. Select Stop, as shown in Figure 1.3.

   Figure 1.3. Select the Stop icon to stop IIS.

   

3. To start IIS again, all you need to do is click the Play icon.

Virtual Directories

I’ve already briefly introduced the concept of virtual directories, which are a key mechanism in IIS; now I’d like to define a virtual directory a little more clearly.

A virtual directory is simply a name (or alias) that points to a local folder or network share on the server. This alias is then used to access the Web application held in that physical location. For instance, imagine your company has a Web server that serves documents from C:\Inetpub\wwwroot\mySiteA. Your users can access these documents through this URL:

http://www.mycompany.com/mySiteA/

You could also set up another physical location as a different virtual directory in IIS. If, for instance, you were developing another Web application, you could store the files for it in C:\dev\newSiteB. You could then create in IIS a new virtual directory called, say, CoolPages, which maps to this location. This new site would then be accessible through this URL:

http://www.mycompany.com/CoolPages/

As this application is in development, you would probably want to set IIS to hide this virtual directory from the public until the project is complete. Your existing Website would still be visible.

Let’s create a virtual directory on your server now:

1. Right-click on Default Web Site and select Virtual Directory from the New submenu. The Virtual Directory Creation Wizard will appear. Click Next.

2. Type in an alias for your virtual directory. I’ll type in WebDocs. Click Next.

3. Browse for the directory in which your application is located. For this example, I’m going to choose the My Pictures folder located within the My Documents directory. Click Next.

4. Set Access Permissions for your directory. Typically, you’ll want to check Read, Run scripts, and Browse. You will not need to select Write until we get into accessing the file system, discussed in Chapter 15, Working with Files and Email. Click Next.

5. Click Finish.

Once your new virtual directory has been created, it will appear within the Website list as shown in Figure 1.4.

Figure 1.4. Once the virtual directory has been created, it will appear within the list of sites.

Now, if you type http://localhost/WebDocs/ in your browser, IIS will recognize that you’re looking for a Website held in the My Pictures directory. By default, when we request a virtual directory in this way, IIS looks for an index HTML page such as index.html or default.htm. If there is no index page—in this case there isn’t—IIS assumes we want to see the contents of the requested location. However, viewing the entire content of a location like this is not usually something we want our users to do; they could then freely see and access all the files and directories that make up our Web page. Not only is this a little messy and unprofessional, but it also can provide information to hackers that could let them attack our site. So, by default, IIS won’t allow this—we’ll receive a message reading, “Directory Listing Denied” in our browser.

Bearing that in mind, there are, however, circumstances in which we do want to allow directory listings, so let’s see how we can enable this in IIS. First, we have to right click the virtual directory in the IIS console, and choose Properties. Then, we select the Virtual Directory tab, and check the Directory browsing box. When we click OK and open (or refresh) the same URL in our browser, we’ll see a list of all the files within the My Pictures folder.

The Properties dialog that we’ve just used lets us configure various other useful properties, including:

Virtual Directory

Allows you to configure directory-level properties including path information, virtual directory name, access permissions, etc. Everything that was set up through the wizard is modifiable through this tab.

Document

Allows you to configure a default page that displays when the user types in a full URL. For instance, because default.aspx is listed as a default page, the user needs only to type in http://www.mysite.com/ into the browser’s address bar, rather than http://www.mysite.com/default.aspx. You can easily change and remove these by selecting the appropriate button to the right of the menu.

Directory Security

Provides you with security configuration settings for the virtual directory.

HTTP Headers

Gives you the ability to forcefully control page caching on the server, add custom HTTP Headers, Edit Ratings (helps identify the content your site provides to users), and create MIME types. Don’t worry about this for now.

Custom Errors

Allows you to define your own custom error pages. Rather than the standard error messages that appear within Internet Explorer, you can customize error messages with your company’s logo and an error message of your choice.

One thing to note at this point is that we can set properties for the Default Web Site node, and choose to have them ‘propagate’ down to all the virtual directories we’ve created. So, let’s now go ahead and enable directory browsing as the default for our Web applications. Please do remember what I’ve said about the dangers of allowing directory browsing on a production Web application, and keep in mind that you should never normally allow it in a publicly accessible environment (even on an intranet). However, during development, this facility can be very handy, as it allows us to navigate and run all our virtual directories by clicking on the listing in our browser, rather than having to type in long URLs each time.

To enable directory browsing:

1. Right-click Default Web Site and select Properties. The Default Web Site Properties dialog will appear.

2. First, we need to remove the default setting which opens up the IIS help documentation for our root directory, so choose the Documents tab.

3. Select iisstart.asp, and click Remove.

4. Now choose the Home Directory tab.

5. Check the Directory Browsing check box and select OK.

6. When the Inheritance Overrides dialog appears, click Select All and then OK.

To try it out, open your browser and type http://localhost/ in the address bar. The directory listing will appear within the browser as shown in Figure 1.5.

Figure 1.5. Enabling directory browsing for the Web server provides you with the ability to view directories in a way that’s similar to the view you’d see within Windows Explorer.

As you create Web applications, you’ll only need to select the directory that the Web application resides in to launch your work, but do remember to disable directory browsing should you later make your IIS Web server publicly visible.

Installing SQL Server Desktop Engine (MSDE)

SQL Server 2000 is Microsoft’s database solution for medium to large companies and enterprises. It is quite a bit more expensive than Access, generally requires its own dedicated “database server”, and, at times, requires the hiring of a certified database administrator (DBA) to maintain; yet it offers a robust and scalable solution for larger Web applications.

I’ll assume that if you’re reading this book, you probably don’t want to invest in something as massive as SQL Server, and that your needs are better suited to something free that’s nearly as powerful for testing and development purposes. If this is the case, then Microsoft’s SQL Server Desktop Engine, or MSDE, is perfect for you. MSDE is Microsoft’s free database alternative to SQL Server. It functions and stores data exactly as SQL Server does, but is licensed for development purposes only.

Once the .NET Framework SDK is installed, installing MSDE is a snap and can be completed as follows:

1. Select Start > Programs > Microsoft Framework SDK, and choose Samples and QuickStart Tutorials.

2. Choose the Download and Install the Microsoft SQL Server 2000 Desktop Engine link. You will be redirected to a download page on Microsoft’s Website.

3. Select Step 1: Download the Microsoft SQL Server 2000 Desktop Engine (68.4 MB).

4. Save the file onto your hard drive. At nearly 70 MB, this may take some time, so you may want to move onto the section called “Your First ASP.NET Page” later in this chapter while the download continues, as our first example doesn’t use a database. Once the download is done, come back and continue the installation process.

5. Double-click the downloaded file and follow the instructions to unpack the MSDE setup files.

6. Open the Command Prompt by selecting Start > Run; type cmd, and select OK.

7. Change to the directory to which you extracted the files using cd on the command line. MSDE extracts to C:\sql2ksp3\MSDE by default.

8. Type the following command (all on one line) in the MSDE directory to set up MSDE:

   Setup.exe /qb+ INSTANCENAME=NetSDK DISABLENETWORKPROTOCOLS=1
   SAPWD=PASSWORD

   The complete set of commands is shown in Figure 1.6.

   Figure 1.6. Install MSDE by running the command line executable and setting necessary parameters.

   

   It’s a good idea to set a suitable system administrator password using the SAPWD parameter as shown above, although you can apply the traditional blank password by using the BLANKSAPWD=1 parameter instead.

9. MSDE will now install.

10. Restart your computer for changes to take effect.

If all goes well, when the computer restarts, you’ll notice in the task bar tray a small icon that looks like a cylinder with a play icon on top, as shown in Figure 1.7.

Figure 1.7. MSDE runs out of sight within the task bar tray.

That icon represents the database Service Manager. It lets you start and stop the database engine; all you have to do is double-click that icon within the task bar tray. Double-click the icon now to open the Service Manager Dialog, where you can select the Play icon to start the service, or the Stop icon to stop the service.

In some cases, you may not see either a green triangle or a red square; instead, you see an empty white circle. When you open Service Manager, you’ll see the message “Not Connected” appear in the status bar at the bottom. You’ll need to type YourComputer\netsdk in the Server drop-down (where YourComputer is the name of your computer), and click Refresh services. MSDE should then connect, and the green triangle should appear.

Installing and Configuring Web Data Administrator

In order to use MSDE effectively, you’ll need some sort of administration tool to work with your databases. Web Data Administrator is another free tool provided by Microsoft that allows you to manage your instance of MSDE locally and remotely using a Web-based interface. You can download this program from Microsoft’s developer site. Scroll to the bottom of that page and you’ll find two search boxes. Leave the top one at All, and type Web Data Administrator in the bottom one, then click search. The search results should include the correct page.

Once you’ve downloaded it, simply double-click the .msi file to install. Once installed, Web Data Administrator can be accessed through your browser at the URL http://localhost/SqlWebAdmin, but before it can be used, you’ll need to enable what is known as SQL Mixed Mode authentication.

This involves making a small change to the registry, but don’t be put off. If you follow these instructions exactly, you won’t do any harm. Let’s do it! Click Start, then Run…. In the dialog, type regedit and press Enter to open the registry editor. Now expand the HKEY_LOCAL_MACHINE node in the left hand pane, then expand the SOFTWARE node. Next, find and open the Microsoft node, and, inside that, open one labeled Microsoft SQL Server. In there, you should find a node called NETSDK, which contains another, called MSSQLServer. Select that node, and find the key (in the right hand pane) called LoginMode. Double-click that, and change its Value data from 1 to 2, then click OK. Now, close regedit, and restart your computer. Phew! That was a bit of a trek, but I hope you found it easier in practice than it appears on paper!

Now, open the Web Data Administrator URL given above. You’ll be asked for the login, password, and server name for your instance of MSDE. Type sa in the user name box, and the password that you supplied during the installation of MSDE. If you’re unsure what the name of your server is, double-click the database engine icon within the task bar tray. The name of your server is located within the server drop-down menu.

Once you’ve done this and clicked Login, you will see a list of the databases that are currently available from MSDE, as shown in Figure 1.8.

Figure 1.8. Web Data Administrator allows you to work with your databases within MSDE.

More information on Web Data Administrator, MSDE, and databases will be covered in Chapter 6, Database Design and Development.

For your first run at ASP.NET, we’ll create the simple example shown in Figure 1.9.

Figure 1.9. We’ll create a simple ASP.NET page that says "Hello there" and displays the time.

Let’s get started! Open your text editor (Notepad^[2] is fine). If you have software that creates ASP.NET pages automatically, such as Visual Studio .NET, please do not use it yet. These programs provide lots of powerful tools for building complex ASP.NET pages in a hurry, but for simple examples like this one, they tend to get in the way, rather than provide assistance.

Open your text editor, and start by entering the plain HTML for our page:

<html>
<head>
<title>My First ASP.NET Page</title>
</head>
<body>
<p>Hello there!</p>
<p>The time is now: </p>
</body>
</html>

So far, so good, right? Now, we’ll add some ASP.NET code that will create the dynamic elements of the page, starting with the time.

<html>
<head>
<title>My First ASP.NET Page</title>
</head>
<body>
<p>Hello there!</p>
<p>The time is now: <asp:Label runat="server" id="lblTime" /></p>
</body>
</html>

We’ve added an <asp:Label> tag to the document. This is a special tag that lets us insert dynamic content into the page. The asp: part of the tag name identifies it as a built-in ASP.NET tag. ASP.NET comes with numerous built-in tags; <asp:Label> is arguably the simplest.

The runat="server" attribute identifies the tag as something that needs to be handled on the server. In other words, the Web browser will never see the <asp:Label> tag; ASP.NET sees it and converts it to regular HTML tags before the page is sent to the browser. It’s up to us to write the code that will tell ASP.NET to replace this particular tag with the current time.

To do this, we must add some script to our page. Like ASP before it, ASP.NET gives you the choice of a number of different languages to use in your scripts. The two most common languages are Visual Basic.NET (VB.NET) and C# (pronounced “C sharp”). Let’s take a look at examples using both. Here’s a version of the page in VB.NET:

<html>
<head>
<title>My First ASP.NET Page</title>
<script runat="server" language="VB">
Sub Page_Load(s As Object, e As EventArgs)
  lblTime.Text = DateTime.Now.ToString()
End Sub
</script>
</head>

<body>
<p>Hello there!</p>
<p>The time is now: <asp:Label runat="server" id="lblTime" /></p>
</body>
</html>

Here’s the same page written in C#:

<html>
<head>
<title>My First ASP.NET Page</title>
<script runat="server" language="C#">
protected void Page_Load(Object s, EventArgs e)
{
  lblTime.Text = DateTime.Now.ToString();
}
</script>
</head>

<body>
<p>Hello there!</p>
<p>The time is now: <asp:Label runat="server" id="lblTime" /></p>
</body>
</html>

Both versions of the page achieve exactly the same thing. If you’ve never done any server-side programming before, this may be starting to look a little scary. Let’s break down the new elements of this page:

<script runat="server">

This tag, otherwise known as a code declaration block, marks the start of server-side code. Like the <asp:Label> tag, this <script> tag uses the runat="server" attribute to let ASP.NET know that the tag should be processed before sending the page to the browser.

Sub Page_Load(s As Object, e As EventArgs)

protected void Page_Load(Object s, EventArgs s) {

I won’t go into too much detail here. For now, all you need to know is that you can write script fragments that are run in response to different events, such as a button being clicked or an item being selected from a drop-down list. What the first line basically says is "execute the following script whenever the page is loaded." Note that C# groups code into blocks with curly braces, while Visual Basic tends to use statements such as End Sub to mark the end of a particular sequence. So, the curly brace in the C# code above ({) marks the start of the script that will be executed when the page loads for the first time. For the technically minded, the code we’ve just seen is a method definition for a page load event handler, which is essentially the code that the server runs when the page is requested for the first time.

Finally, here’s the line that actually displays the time on the page:

  lblTime.Text = DateTime.Now.ToString()

  lblTime.Text = DateTime.Now.ToString();

You can see that these two .NET languages have much in common, because they are both built on the .NET Framework. In fact, the only difference with the above line is that C# ends code lines with a semicolon (;). In plain English, here’s what this line says:

Note that lblTime is the value we gave for the id attribute of the <asp:Label> tag where we want to show the time. So, lblTime.Text, the Text property of lblTime, refers to the text that will be displayed by the tag. DateTime is a class that’s built into the .NET Framework, and which lets you perform all sorts of useful functions with dates and times. There are thousands of these classes that do all sorts of useful things within the .NET Framework. These classes are also known as the .NET Framework Class Library.

The DateTime class has a property called Now that always contains the current date and time. This Now property has a method called ToString() that expresses that date and/or time as text (a segment of text is commonly called a string in programming circles). Classes, properties, and methods: these are all important words in the vocabulary of any programmer, and we’ll discuss them later on in the book. For now, all you need to take away from this discussion is that DateTime.Now.ToString() will give you the current date and time as a text string, which you can then tell your <asp:Label> tag to display. The rest of the script block simply ties up loose ends:

End Sub
</script>

}
</script>

The closing (End Sub) and (}) mark the end of the script to be run when the page is loaded, and the </script> tag marks the end of the script block.

Create a new subdirectory of C:\Inetpub\wwwroot on your Web server, and save your file there under the name FirstPage.aspx. Now, open your browser and point type this URL in the address bar:

Replace test with the name that you gave to the directory in which you saved the file. You should see a page similar to the one we saw in Figure 1.9.

If the time isn’t displayed, chances are that you opened the file directly in your browser instead of loading it through your Web server. Because ASP.NET is a server-side language, your Web server needs to access the file before it’s sent to your browser for display. If it doesn’t get access to the file, the ASP.NET code is never converted into HTML that your browser can understand, so make sure you load the page by typing an actual URL (e.g. http://localhost/test/index.aspx), not just a path and filename.

With the page displayed in your browser, use the View Source feature (View, Source in Internet Explorer) to view the HTML code for the page. Here’s what you’ll see:

<html>
<head>
<title>My First ASP.NET Page</title>
</head>
<body>
<p>Hello there!</p>
<p>The time is now: <span id="lblTime">10/13/2003 1:55:09 
PM</span></p>
</body>
</html>

Notice that all the ASP.NET code has gone! Even the script block has been completely removed, and the <asp:Label> tag has been replaced by a <span> tag (with the same id attribute as the <asp:Label> tag that we used) containing the date and time string.

That’s how ASP.NET works. From the Web browser’s point of view, there is nothing special about an ASP.NET page; it’s just plain HTML like any other. All the ASP.NET code is run by your Web server and converted to plain HTML that’s sent to the browser. So far, so good: the example above was fairly simple. The next chapter will get a bit more challenging as we begin to introduce you to some valuable programming concepts.

The official Microsoft ASP.NET support Website can be found at http://www.asp.net/. As you develop ASP.NET Web applications, you will undoubtedly have questions and problems that need to be answered. The ASP.NET support Website was developed by Microsoft as a portal for the ASP.NET community to answer the questions and solve the problems that developers have while using ASP.NET. The support Website provides useful information, such as news, downloads, articles, and discussion forums. You can also ask questions of the experienced community members in the SitePoint Forums.

In this chapter, you learned about .NET. You also learned of the benefits of ASP.NET and that it’s a part of the .NET Framework. First, you learned about the constructs of ASP.NET and how to locate and install the .NET Framework. Then, we explored the software that’s required not only for this book, but also in order for you or your company to progress with ASP.NET.

You’ve gained a solid foundation in the world of ASP.NET! The next chapter will build on this knowledge and begin to introduce you to ASP.NET in more detail, including page structure, languages to use, programming concepts, and form processing.