C# in Depth

ABOUT THIS BOOKxxvtopics are often understood “just well enough” by C#1 developers, but C#2 and 3develop them significantly, so a solid grounding is required in order to make the mostof the new features.Chapter 3 tackles the biggest feature of C#2, and potentially the hardest to grasp:generics. Methods and types can be written generically, with type parameters standingin for real types which are specified in the calling code. Initially it’s as confusing as thisdescription makes it sound, but once you understand generics you’ll wonder how yousurvived without them.If you’ve ever wanted to represent a null integer, chapter 4 is for you. It introducesnullable types, a feature built on generics and taking advantage of support in the language,runtime, and framework.Chapter 5 shows the improvements to delegates in C#2. You may have only useddelegates for handling events such as button clicks before now. C#2 makes it easier tocreate delegates, and library support makes them more useful for situations otherthan events.In chapter 6 we examine iterators, and the easy way to implement them in C#2.Few developers use iterator blocks, but as LINQ to Objects is built on iterators, theywill become more and more important. The lazy nature of their execution is also a keypart of LINQ.Chapter 7 shows a number of smaller features introduced in C#2, each making lifea little more pleasant. The language designers have smoothed over a few rough placesin C#1, allowing more flexible interaction with code generators, better support forutility classes, more granular access to properties, and more.Chapter 8 once again looks at a few relatively simple features—but this time inC#3. Almost all the new syntax is geared toward the common goal of LINQ but thebuilding blocks are also useful in their own right. With anonymous types, automaticallyimplemented properties, implicitly typed local variables, and greatly enhancedinitialization support, C#3 gives a far richer language with which your code canexpress its behavior.Chapter 9 looks at the first major topic of C#3—lambda expressions. Not contentwith the reasonably concise syntax we saw in chapter 5, the language designers havemade delegates even easier to create than in C#2. Lambdas are capable of more—theycan be converted into expression trees: a powerful way of representing code as data.In chapter 10 we examine extension methods, which provide a way of fooling thecompiler into believing that methods declared in one type actually belong to another.At first glance this appears to be a readability nightmare, but with careful considerationit can be an extremely powerful feature—and one which is vital to LINQ.Chapter 11 combines the previous three chapters in the form of query expressions,a concise but powerful way of querying data. Initially we concentrate on LINQ toObjects, but see how the query expression pattern is applied in a way which allowsother data providers to plug in seamlessly.Chapter 12 reaps the rewards of query expressions combined with expressiontrees: it shows how LINQ to SQL is able to convert what appears to be normal C# intoLicensed to Rhona Hadida