Microsoft Visual C++ .NET Professional Projects - Premier Press

named myapplication by using ASP.NET, a folder named myapplication is created automatically in IIS.

The application is created in the root directory of IIS only when you use Visual Studio .NET applications to create ASP.NET applications. However, if you are using a text editor, you will need to create the application root directory manually. You can create an application root directory in either of two ways:

By creating a virtual directory

By marking a folder as an application

Creating a Virtual Directory

As mentioned in the previous section, you can create an application root directory manually by creating a virtual directory. You create a virtual root directory to publish the page so that the page can be deployed on a Web site. The following are the features of a virtual root directory that make it suitable for creating an application root directory:

A virtual directory does not need to be located in the physical structure of the root directory of the Web server. The location could be completely different or even could be on a remote computer.

Different virtual directories can point to the same set of files.

When you create a virtual directory and point it to your application that is stored in the root directory of the Web server, the virtual directory becomes the application root directory for your application.

You can create a virtual directory by following these steps:

1.Open the IIS MMC from the Internet Service Manager. Then, rightclick on Default Web Site.

2.Choose New, Virtual Directory from the context menu. The Virtual Directory Creation Wizard appears.

3.Click on Next on the Welcome screen to proceed. You are prompted to enter an alias for the virtual directory.

4.Type an alias name for your virtual directory and click on Next to move to the next screen.

5.Type the name of your virtual directory. Click on Next. The name will appear in the IIS MMC. The next screen prompts you to enter the name of the content directory that you want to publish on the Web site.

Clipboard Ring. Contains pieces of text. Text that you cut or copy becomes a part of this category.

General. Contains the Pointer tool. You can choose to add controls such as Buttons and custom controls to this category.

You can insert the Web Forms controls by dragging the control from the Toolbox to the Web Forms page. An alternative way to add a control is by double-clicking on the control and then specifying the coordinates of the location on which you want to place it on the form. Note that when you drag a control to the Web Forms page, the code for the control is by default added in the ASPX file.

Using the HTML View of the ASPX File

You can also add server controls programmatically by writing the required ASP.NET code in HTML view of the ASPX file of your Web form. Consider an example where you add a text box by using ASP.NET code:

<asp:TextBox id = “MyTextBox” runat = “server” Text = “Greetings”></asp:TextBox>

To view the output of the preceding code, you need to switch to Design view.

Using the Code-Behind File

In the previous section, you learned about adding controls at design time. However, ASP.NET gives you the power and flexibility of creating a control at run time. You can do so by creating an instance of the control class that inherits the WebControl base class. Consider the following code that creates a text box by using Visual C# code:

System.Web.UI.WebControls.TextBox Text_Box=new TextBox();

this.Controls.Add(Text_Box);

In the preceding code, a TextBox control is added by using the Add method of the

ControlCollection class.

Setting Properties for Web Controls

Once you have added a server control to a Web Forms page, you can define the control’s properties. All server controls have common properties, referred to as base properties, which are inherited from the WebControl base class. In addition to the base properties, each control also possesses its own set of properties. You have the option of specifying these properties either at design time or at run time.

526 Project 4 CREATING A MANAGED EXTENSIONS CLASS LIBRARY

Setting Properties at Design Time

You can set properties for a control at design time in either of two ways:

Using the Properties window. You can access the properties for a control by opening the Properties window. To open the Properties window for the control, select the control and then select Properties from the pop-up menu. You can also open the window by choosing Properties window from the View menu or by pressing F5.

Figure 15-4 displays the Properties window for a TextBox control.

FIGURE 15-4 Properties window for a TextBox control

Writing ASP.NET code. You can also add a control to the Web Forms page by writing the code for specifying the properties of the control. For example, to set the Enabled property of a TextBox control in the ASPX file, you can use the following code:

<asp:TextBox Id = “Text_Box” runat = “server” Enabled =

False></asp:TextBox>

Setting Properties at Run Time

You might want a control to be displayed only when a certain event occurs or a condition returns true. For example, you might want to display a control only when the user selects the right answer. In such a situation, you can set properties for a control at run time. However, to do so, you need to write the code for chang-

528 Project 4 CREATING A MANAGED EXTENSIONS CLASS LIBRARY

Table 15-4 (continued)

You can handle the events by either using the code-behind file or the ASPX file. To better understand this concept, consider the example of a Button control. A Button control possesses its own Click event. There are two ways that you can handle this event: use the code-behind file or use the ASPX file.

The steps to handle the Click event of the Button control using the code-behind file are as follows:

1.Open the code-behind file by either using the Solution Explorer or pressing the F7 key.

2.Write the handler for the control’s event. To do so, select the name of the control from the Class Name list. Next, select the event from the Method Name list.

Consider the following example:

private void AcceptButton_Click(object sender, System.EventArgs e)

{

}

In the preceding code:

The ID of the button is specified as AcceptButton.

AcceptButton_Click is the event handler for the Click event of the button with the ID AcceptButton.

The procedure accepts two arguments.

The first argument contains an object called event sender.

The second argument contains the data for the event.

The Handles keyword is used to associate the Click event with the event

handler; i.e., AcceptButton_Click.

The next step is to modify the code in the event handler to add the desired tasks. You can also create event handlers for server controls by using the ASPX file. Consider the preceding example of a Button control with ID AcceptButton. The creation and association of the event handler with the Click event is done in two steps:

1.Edit the code for the control in the ASPX file. This is used to specify the event handler for the Click event:

<asp:Button Id = “AcceptButton” runat = “server” OnClick =

“AcceptButton_Click”></asp:Button>

In this code snippet, OnClick = “AcceptButton_Click” is the event that should be called when the Click event of the button is generated.

2.Write the AcceptButton_Click event handler in the ASPX file. Recall that all the code is written within the <Script> tag.

The following code shows where to add an event handler:

<script language=”cs” runat=”server”>

private void AcceptButton_Click(object sender, System.EventArgs e)