【正文】 (ref saveChanges, ref missing, ref missing)。 (which is not an acronym, despite appearances) is a framework for building web applications. Not all frameworks are about user interfacesWindows Communication Foundation (WCF) is designed for building services accessed over the work by other puter systems, for instance. These three categories are not strict, as quite a few classes fit into two. For example, the parts of the class library that provide access to the filesystem are not just thin wrappers around existing Win32 APIs. They add new objectoriented abstractions, providing significant functionality beyond the basic file I/O services, so these types fit into both the first and second categories. Likewise, frameworks usually need to integrate with underlying services to some extent— for example, although the Windows Forms UI framework has a distinctive API of its own, a lot of the underlying functionality is provided by Win32 ponents. So the three categories here are not strict. They just offer a useful idea of what sorts of things you can find in the class libraries. Language Style C is not the only language that runs on the .NET Framework. Indeed, support for multiple languages has always been a key feature of .NET, reflected in the name of its runtime engine, the CLR or Common Language Runtime. As this name implies, .NET is not just for one language—numerous languages have access to the services of the .NET Framework class library. Why might you choose C over the others? We already mentioned one important reason: C was designed specifically for .NET. If you are working with .NET technologies such as WPF or , you’ll be speaking their language if you work in C. Compare this with C++, which supports .NET through extensions to the original language. The extensions are carefully thought out and work well, but code that uses .NET libraries just looks different from normal C++, so programs that bridge the worlds of .NET and standard C++ never feel pletely coherent. And the dual personality often presents dilemmasshould you use standard C++ collection classes or the ones in the .NET class library, for example? In native .NET languages such as C, such questions do not emerge. But C is not unique in this respect. Visual Studio 2020 ships with three languages designed for .NET: C, , and F. (Although follows on from its Visual Basic predecessors, it was radically different in some important ways. It is a native .NET language with a VBlike syntax rather than VB 6 with .NET capabilities bolted on.) The choice between these languages es down to what style of language you prefer. F is the odd one out here. It’s a functional programming language, heavily influenced by a language called ML. Back in 1991, when your authors were firstyear students, our university’s puter science course chose ML for the first programming language lectures in part because it was so academic that none of the students would previously have e across anything like it. F is still at the academic end of the spectrum despite having climbed far enough down the ivory tower to be a standard part of a mainstream development environment. It excels at plicated calculations and algorithms, and has some characteristics that can help with parallel execution. However, as with many functional languages, the cost of making some hard problems easier is that a lot of things that are easy in more traditional languages are remarkably hard in F functional languages are adept at plex problems, but can be clumsy with simple ones. It seems likely that F will mostly be used in scientific or financial applications where the plexity of the putation to be performed dwarfs the plexity of the code that needs to act on the results of those calculations. While F feels distinctly other, and C have a lot of similarities. The most obvious factor in choosing between these is that is easier to learn for someone familiar with Visual Basic syntax, while C will be easier for someone familiar with a Clike language. However, there is a subtler difference in language philosophy that goes beyond the syntax. Composability A consistent theme in the design of the C programming language is that its creators tend to prefer generalpurpose features over specialized ones. The most obvious example of this is LINQ, the Language Integrated Query feature added in C . Superficially, this appears to add SQLlike query features to the language, providing a natural way to integrate database access into your code. Example 12 shows a simple query. Example 12. Data access with LINQ var californianAuthors = from author in where == CA select new { , }。 (authorName)。本節(jié)您現(xiàn)在正在閱讀的 是一個例外，當(dāng)然，最主要的原因是，我們期望與 C＃ 已經(jīng)熟悉的人通過這本書在書店瀏覽尋找我們的新功能的覆蓋面。而不是要求開發(fā)商與過去決裂 NET 提供的連續(xù)性它可能是內(nèi)置的組件和服務(wù)直接或 Windows 內(nèi)置。換句話說，這一點是使開發(fā)人員的生產(chǎn)力。例如，早期我們提到， C＃可以自動內(nèi)存管理的某些方面，一個臭名昭著 的 C + +代碼中的錯誤源。 組合性 設(shè)計 C編程語言 的一個一致的主題是，它的開發(fā)者傾向于選擇專門的通用功能。 Visual Studio 2020 為 .NET 設(shè)計了 三種語言： NET的 C＃， 和 F＃ 。例如， 類庫提供訪問文件系統(tǒng)的部分不只是薄的包裝圍繞現(xiàn)有的 Win32 API。 C中還采用了功能編程的支持，這是以前學(xué)術(shù)語言中的一個非常強大的功能。最近，微軟的Sliverlight 平臺使得可以用 C編寫可以在網(wǎng)頁瀏覽器上運行的 Inter 應(yīng)用程序。 為什么是 C？為什么是 .NET？ 編程語言的存在，可以讓開發(fā)人員的開發(fā)工作更加的有效率。 第一組包括的實用工具如字典、列表和其他 集合類，以及字符串處理工具如正規(guī)表達引擎。 語言風(fēng)格 C并不是唯一一 個在 .NET Framwork 上運行的語言。這些語言之間的選擇歸結(jié)到什么風(fēng)格的需要的語言。 foreach (var author in californianAuthors) { (author)。雖然 C＃編譯器緊密合作，使這成為可能的運行，提供您的代碼如何使用對象和數(shù)據(jù)的必要的信息，這是最終運行垃圾收集工作。已經(jīng)提到，符合 CLR 的能力，以驗證該代碼輸入安全規(guī)則，在執(zhí)行前，裁決了整體的安全和穩(wěn)定的錯誤類。微軟的Silverlight 可以運行的 Mac OS X 以及 Windows 的 C＃和 代碼。 object fileName = 。 這理解起來要簡單的多 ，因為代碼只包含有關(guān)細(xì)節(jié)。 and as alread