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740 Project 6 CREATING A MOBILE APPLICATION

mobile device.The content of a site in a mobile device is not shown as a single or multiple page Web site. Instead, the entire content of the site is displayed in the form of smaller but logical chunks of data presented in a linear manner. These chunks of data are displayed in the controls on a mobile Web form.

When the data in the controls needs to be displayed, these controls are broken down into smaller units called screens by the Mobile Internet Toolkit. The size of the screen is determined by the type of device on which you need to deploy the mobile application. However, while designing a mobile application, you need not worry about the different screen sizes of various mobile devices. The Mobile Internet Toolkit allows you to create applications once for various mobile devices. The code then adapts to the various form factors, such as the screen size, bandwidth, and memory of the accessing client device.

As discussed earlier, the mobile Web forms toolbox contains several tools that you can use to create a mobile application. In addition, the Mobile Internet Toolkit allows you to create custom Web forms tools for your application. In the following sections, I will discuss about the standard controls available. You can then use these standard controls to design a MobileTimeRetriever application.

The Form Control

I have already discussed Form controls.A Form control is a container used to store and display other mobile Web forms controls. At run time, a single form is displayed at a time. However, you can access multiple forms on a mobile Web page by using the same URL address of the Web page. To add a form to your mobile Web forms page, drag the Form control from the mobile Web forms toolbox to the mobile Web forms page.

The Panel Control

The Panel control is similar to a Form control in that it can be used to logically group related controls. However, unlike a Form control, you cannot place a Panel control directly on the Web forms page. A Panel control needs to be included in a Form control or another Panel control. Alternatively, you cannot nest a Form control within a Panel control. If you try to include a Form control within a Panel control, an error is generated, as shown in Figure 32-8.

FIGURE 32-8 The error displayed on including a Form cont rol within a Panel control

In addition to organizing controls in a Panel control, you can use a Panel control to set the properties of all the controls within the same Panel control.

The MobilePage Control

In addition to the Form and Panel controls, Visual Studio .NET provides you with another control called the MobilePage control, which groups related controls. The MobilePage control acts as a container for all other containers in a mobile Web application. This implies that the MobilePage control is the outermost container in a mobile Web application and has an associated URL address. The MobilePage control has a class associated with it called the MobilePage class. It is the base class for all the controls in a mobile Web application and stores the information about the style and other properties that are common to the controls in a MobilePage control. Figure 32-9 shows a MobilePage control.

742 Project 6 CREATING A MOBILE APPLICATION

FIGURE 32-9 The MobilePage control

NOTE

The MobilePage control is not packaged as a control in the mobile Web forms controls toolbox.Visual Studio .NET automatically creates a MobilePage control for your application. You can add one or more Form controls to the MobilePage control. In addition, the MobilePage control may contain a StyleSheet control.

The Label Control

A mobile Web form Label control is similar to a Windows forms Label control. A Label control is used to display any text in mobile application. You can add text to a Label control either by setting the Text property of the Label control or by programmatically changing the text of the Label control. To add a Label control to your form, drag the Label control from the mobile Web forms toolbox to the Form or Panel control.

744 Project 6 CREATING A MOBILE APPLICATION

To display the text as it appears in Figure 32-10, add the following text to the Text property of the control.

A TextView control is used to display text in a mobile application. <br>

You can display text in multiple lines in a TextView control.

The Link Control

A Link control is a text-based control that creates a text hyperlink. You can use this hyperlink to connect to another form or another mobile Web page. You can specify the name of the form or the URL of the page in the NavigateURL property of the control.

The PhoneCall Control

A PhoneCall control is another text-based control that is used to store a phone number to be called. When a PhoneCall control is accessed from a mobile device, such as a cellular phone, the PhoneCall control dials the number specified in the control.

The List Control

A List control is used to display a list of items in a mobile device. A user can select any item from the List control. To add items to a List control, use the Items property of the control. You can also associate the List control to a data source to display a list of items from a data source. Perform the following steps to display a list of items in a List control.

1.Drag a List control from the mobile Web forms toolbox to a mobile Web form.

2.Select the List control to make it active.

3.In the Properties window of the list control, change the ID property of the control to lstCountry.

If the Properties window is not visible, press the F4 key or select the Properties Window option on the View menu.

4.Click on the ellipsis button of the Items property to add items to the List control.

746 Project 6 CREATING A MOBILE APPLICATION

The SelectionList Control

A SelectionList control is similar to a List control because it can be used to display a list of items. However, you can use a SelectionList control to provide users with a choice of options in the form of a drop-down list, radio buttons, check boxes, and combo boxes. A user can select one or more options from a SelectionList control. When a user selects an item from the list, the selected item is not automatically posted to the server. To do this, the user needs to explicitly click on the Command control. You will learn about the Command control later in this chapter.

To display the list of countries as you did in the previous section, you can also use a SelectionList control instead of a List control.To add items to the SelectionList control, use the Items property of the control. The procedure for adding items to a SelectionList control is the same as that of adding items to a List control. Figure 32-12 shows the items added to a SelectionList control and a List control.

FIGURE 32-12 The items added to a SelectionList control and a List cont rol

The ObjectList Control

An ObjectList control is also used to display a list of items in a mobile application. However, the list of items in an ObjectList control includes the list of data objects. To display a list of data objects in an ObjectList control, you need to bind the ObjectList control to a data source. You can do this by using the DataSource property of the control.