【正文】 寫一個代碼 “當一些人詢問名字屬性的值時，從數(shù)據(jù)庫中讀名字，并且返回這個名字用 string類型” 函數(shù) 一個函數(shù)是一種可以隨時使用的代碼，代碼。 類能夠包含代碼和數(shù)據(jù)。 接口 C提供了接口，它聚集了屬性，方法，和闡述一套功能的事件。如果我們使用一個接口在這個例子中，你的 DLL添加項可以應用于一個接口。那么，當你的 CPU不能讀取 MSIL的時候，說明代碼中。 另外一個編譯器使用 MSIL的原因是指令的設置能夠很容易地被一個認證近程讀取。ll learn more about objects in Chapter 8, Writing ObjectOriented Code. For now, think of an object as a collection of data and a set of operations that can be performed on that data. Objectstyle coding could be acplished using C, but the notion of an object was not enforced by the language. If you wanted to structure your code to resemble an object, fine. If you didn39。s name must be read from a database, for example, you can write code that says, when someone asks for the value of the Name property, read the name from the database and return the name as a string. Functions A function is a callable piece of code that may or may not return a value to the code that originally called it. An example of a function would be the FullName function shown earlier, in this chapter, in the Family class. A function is generally associated to pieces of code that return information whereas a method generally does not return information. For our purposes however, we generalize and refer to them both as functions. Functions can have four kinds of parameters: ? Input parameters have values that are sent into the function, but the function cannot change those values. ? Output parameters have no value when they are sent into the function, but the function can give them a value and send the value back to the caller. ? Reference parameters pass in a reference to another value. They have a value ing in to the function, and that value can be changed inside the function. ? Params parameters define a variable number of arguments in a list. C and the CLR work together to provide automatic memory management. You don39。reworking with. Think of metadata as a table of contents for your piled code. The C piler places metadata in the piled code along with the generated MSIL. This metadata accurately describes all the classes you wrote and how they are structured. All of the classes39。ve ever worked with COM (Component Object Model), you may be familiar with type libraries. Type libraries aimed to provide similar table of contents functionality for COM objects. However, type libraries suffered from some limitations, not the least of which was the fact that not all of the data relevant to the object was put into the type library. Metadata does not have this shorting. All of the information needed to describe a class in code is placed into the metadata. You can think of metadata as having all of the benefits of COM type libraries without the limitations . Assemblies Sometimes, you will use C to build an enduser application. These applications are packaged as executable files with an extension of .EXE. Windows has always worked with .EXE files as application programs, and C fully supports building .EXE files. However, there may be times when you don39。s visibility to other objects. C supports public, protected, internal, protected internal, and private accessibility scopes. Variables Variables can be defined as constants. Constants have values that cannot change during the execution of your code. The value of pi, for instance, is a good example of a constant, because its value won39。t care. Objects weren39。正確地訪問內存，型 時。 JIT編譯器的工作是翻譯你的普遍性的 MSIL代碼給機器以便 CPU可以執(zhí)行你的代碼。 屬性 屬性聲明了額外的信息關于你的類對于 CLR。何現(xiàn)有的代碼，它能盡可能少的兼容問題。 C提供了 public，protected， internal， protected internal和 private這些可接近的范圍。一個函數(shù)通常會聯(lián)合一些返回信息的代碼，而一個方法通常不返回信息。而對象和數(shù)組類型被處理成了引用類型。 下面讓我們來看一個叫做 Family的類的 例子。碼并且能想對快地識別代碼。它普遍認可在這個學術上的競爭擴展到包含這個商業(yè)的世界，腦上。你將會學到更多的關于對象的內容在第八章“寫面向對象的代碼”一個對象作為一個數(shù)據(jù)的收集并且設置了一些操作，代碼可以被 C來完成，但是對象的觀念并不能被強制出現(xiàn)在這個語言中。 C剔除了一些使得 C和 C++工作起來很困難的東西。 class Class1 { public string FirstName。你可以使用隱式的轉換策略或者顯式的轉換策略。 ? 輸出的參數(shù)沒有值當他們被傳遞給函數(shù)時， 但是函數(shù)可以給它們值并且將這個值傳回給它的調用者。枚舉類型詳細的定義了一種有關常量的名稱。 讓我們看一個現(xiàn)實世界的 C中有利于舉例說明接口的非常明確的規(guī)則的例子?？赡苄允菦]完沒了的，這也是為什么微軟會包含很多預定義的屬性在 .NET結構里。這里有很多引起 這個的原因。 CPU特定指令設置是為了快速執(zhí)行代碼而優(yōu)化的。s actually good news. C eliminates the things that makes C and C++ difficult to work with. Because all C code is also C++ code, C++ had to retain all of the original quirks and deficiencies found in C. C is starting with a clean slate and without any patibility requirements, so it can retain the strengths of its predecessors and discard the weaknesses that made life hard for C and C++ programmers. Introducing C C, the new language introduced in the .NET Framework, is derived from C++. However, C is a modern, objectedoriented (from the ground up) typesafe language. Language features. The following sections take a quick look at some of the features of the C language. If some of these concepts don39。 and then it uses the GetProcAddress to locate the CEEntry function within the DLL, thus verifying that you followed all the rules necessary to create an addin. This method of creating and loading addins is very burdensome because it burdens the code editor with more verification duties than necessary. If an interface were used in this instance, your addin DLL could have implemented an interface, thus guaranteeing that all necessary methods, properties, and events were present with the DLL itself, and functioning as documentation specified. Attributes Attributes declare additional information about your class to the CLR. In the past, if you wanted to make your class selfdescribing, you had to take a disconnected approach in which the documentation was stored in external files such as IDL or even HTML files. Attributes solve this problem by enabling you, the developer, to bind information to classes — any kind of information. For example, you can use an attribute to embed documentation information i