Mobile Web Development with ASP.NET

ASP.NET Mobile Controls were deprecated by Microsoft and are not recommended for ASP.NET 4.0 mobile web development. Instead, Microsoft recommends using modern approaches like responsive web design, ASP.NET MVC, or CSS media queries to create mobile-friendly applications.

Even when different sets of web pages are targeted at mobile devices, they still run within the same ASP.NET application domain. Consequently, they share the same web.config configurations, application state, and active session data, making the statement false.

The directive <%@ OutputCache Duration="60" %> caches a single version of the page. Without specifying properties like VaryByCustom or VaryByHeader (e.g., User-Agent), mobile devices can receive the cached desktop version of the page. Thus, the statement is false.

The 51Degrees.Mobi library, when used with the WURFL device database, populates the Request.Browser object with far more detailed and accurate device capability information than ASP.NET 4.0 provides by default. It doesn't modify responses, cache pages, or provide readiness checking scripts - its advantage is enhanced device detection.

In ASP.NET, the master page must be set dynamically during or before the Page_PreInit event. Attempting to assign or modify the MasterPageFile property during Page_Init or Page_Load occurs too late in the page lifecycle and throws an InvalidOperationException.

The Session_Start event in Global.asax fires when a new user session begins, making it the ideal place to redirect mobile users to a mobile-specific page at the start of their browser session. The Session_Start in code-behind wouldn't fire at session start, Application_Start is for app-level initialization, and Page_Init is for individual page initialization.

Response.Cache.SetNoTransforms() adds an HTTP header that instructs mobile network transcoders and proxy servers not to modify the content, ensuring your mobile page renders as designed. The other options don't exist in the .NET framework - System.Network and Microsoft.Network don't have such methods, and it's Response not Request.

CSS is a client-side technology that runs in the browser to control visual presentation. Using different CSS for mobile devices allows responsive adaptation without server-side changes. Master pages (A) are server-side constructs, and separate web pages (C) require server-side routing - neither are client-side solutions.

CSS3 Media Queries allow applying different styles based on device characteristics like screen size, orientation, and resolution. They are the core of responsive web design. Media queries do NOT handle business logic (A), master pages (B), or device capability detection (D) - those are server-side or JavaScript concerns.

Responsive design targets screen sizes rather than specific device models, operating systems, or manufacturers. This approach ensures layouts work across current and future devices. Designing for specific device models (A) or OS platforms (B) creates maintenance burden and excludes new devices. Manufacturer-specific design (D) is similarly unsustainable.

In CSS cascade precedence, inline styles (referred to here as 'Inner Style') override internal style sheets (defined in <style> blocks), which in turn override external style sheets (linked .css files), assuming equal specificity. Thus, inner styles take highest precedence.

ASP.NET Mobile Controls were deprecated by Microsoft and are NOT recommended for ASP.NET 4.0 development. Microsoft recommends using CSS media queries, responsive design, and standard web controls instead. The Mobile Controls namespace was designed for older devices and doesn't align with modern web standards.

Mobile and desktop pages in the same ASP.NET application share the same application context, including Session state, configuration, and Application state. The claim that they don't share data is incorrect. They are different views of the same application, not separate applications.

The OutputCache directive caches based on URL and parameters, not device type. Without device-specific caching logic (like VaryByCustom), a mobile device making the same URL request could receive the desktop-cached version. The statement that it will 'never' receive the cached page is false.