【正文】 the control is not processed for either prerendering or rendering. Web controls (but not every HTML control) have an additional property named Enabled. When Enabled has the value False and you are using Inter Explorer version or higher, the control appears ghosted and no longer functions. When used with other browsers, such as Netscape Navigator, the control might not appear ghosted, but it does not function. Disabling View State In certain circumstances, you might want to disable view state for an individual control or for an page as a whole. For example, you might have a control that contains a lot of data (imagine a RadioButtonList control with 1,000 options). You might not want to load the data into the hidden __VIEWSTATE form field if you are worried that the form data would significantly slow down the rendering of the page. Using Rich Controls In the following sections, you learn how to use three of the more featurerich controls in the framework. You learn how to use the Calendar control to display interactive calendars, the AdRotator control to display rotating banner advertisements, and the HTMLInputFile control to accept file uploads. XIX 目 錄 1 緒論 ..................................................................................................................... 21 開(kāi)發(fā)背景 ............................................................................................................ 21 系統(tǒng)開(kāi)發(fā)的意義 ................................................................................................ 21 開(kāi)發(fā)者的主要工作 ............................................................................................ 21 論文的組織結(jié)構(gòu) ................................................................................................ 22 2 相關(guān)技術(shù)介紹 .................................................................................................. 23 BREW SDK 介紹 ............................................................................................... 23 BREW 模擬器介紹 ........................................................................................... 24 OOC 介紹 .......................................................................................................... 25 ClassInC .................................................................................................... 25 AbstractInterfaceInC................................................................................. 25 3 手機(jī)電話(huà)簿的設(shè)計(jì)與實(shí)現(xiàn) .......................................................................... 26 系統(tǒng)設(shè)計(jì) ............................................................................................................ 26 系統(tǒng)設(shè)計(jì)任務(wù) ............................................................................................. 26 系統(tǒng)模塊設(shè)計(jì) ............................................................................................. 26 功能模塊設(shè)計(jì) ............................................................................................. 27 數(shù)據(jù)存儲(chǔ)結(jié)構(gòu) .................................................................................................... 27 數(shù)據(jù)存儲(chǔ)結(jié)構(gòu) ............................................................................................. 27 數(shù)據(jù)庫(kù)結(jié)構(gòu)設(shè)計(jì) ......................................................................................... 27 系統(tǒng)實(shí)現(xiàn) ............................................................................................................ 28 基本操作說(shuō)明 ............................................................................................. 28 重要模塊實(shí)現(xiàn)細(xì)節(jié) ....................................................。s preferences. Finally, imagine that you want to break the tax form into multiple pages so that a person views only one part of the tax form at a time. XVIII In the following sections, you learn about the properties that you can use to hide and display controls in a form. You learn how to use the Visible and Enabled properties with individual controls and groups of controls to hide and display page content. Using the Visible and Enabled Properties Every control, including both HTML and Web controls, has a Visible property that determines whether the control is rendered. When a control39。 they are the formatting properties of the base control class. Next, you learn how to apply Cascading Style Sheet styles and classes to Web controls. 3. Performing Form Validation with Validation Controls Using Clientside Validation Traditionally, Web developers have faced a tough choice when adding form validation logic to their pages. You can add form validation routines to your serverside code, or you can add the validation routines to your clientside code. The advantage of writing validation logic in clientside code is that you can provide instant feedback to your users. For example, if a user neglects to enter a value in a required form field, you can instantly display an error message without requiring a roundtrip back to the server. People really like clientside validation. It looks great and creates a better overall user experience. The problem, however, is that it does not work with all XVI browsers. Not all browsers support JavaScript, and different versions of browsers support different versions of JavaScript, so clientside validation is never guaranteed to work. For this reason, in the past, many developers decided to add all their form validation logic exclusively to serverside code. Because serverside code functions correctly with any browser, this course of action was safer. Fortunately, the Validation controls discussed in this chapter do not force you to make this difficult choice. The Validation controls automatically generate both clientside and serverside code. If a browser is capable of supporting JavaScript, clientside validation scripts are automatically sent to the browser. If a browser is incapable of supporting JavaS