.NET/ASP.NET/C#/VB.NET PDF Document SDK

Union types can have member functions too. You define them in the same way as for record types. The next example shows a union type, DrinkAmount, that has a function added to it: #light type DrinkAmount = | Coffee of int | Tea of int | Water of int with override x.ToString() = match x with | Coffee x -> Printf.sprintf "Coffee: %i" x | Tea x -> Printf.sprintf "Tea: %i" x | Water x -> Printf.sprintf "Water: %i" x end let t = Tea 2 print_endline (t.ToString()) The results of this example, when compiled and executed, are as follows: Tea: 2 Note how this uses the keyword override in place of the keyword member. This has the effect of replacing, or overriding, an existing function of the type. This is not that common a practice with function members associated with F# types because only four methods are available to be overridden (ToString, Equals, GetHashCode, and Finalize) that are inherited from System.Object by every .NET type. Because of the way some of these methods interact with the CLR, the only one I recommend overriding is ToString. Only four methods are available for overriding because record and union types can t act as base or derived classes, so you cannot inherit methods to override (except from System.Object).

how to print 2d barcode in excel, formula to create barcode in excel 2010, create barcode macro excel, active barcode excel 2010 download, bulk barcode generator excel, microsoft excel barcode font free, barcode generator excel kostenlos, create barcode excel 2013, can i create barcodes in excel 2010, barcodes excel 2003,

Unfortunately, we don t all own Macs, and at least for now, we won t be able to run Mac OS X on an Intel box Still, that doesn t mean you can t share a bit in the features of Dashboard In fact, in the next section, you ll use Ajax along with some freely available Web Services to mimic Dashboard in a browser..

276-1711 276-1122 271-1321 272-1014

Object expressions are at the heart of succinct object-oriented programming in F#. They provide a concise syntax to create an object that inherits from an existing type. This is useful if you want to provide a short implementation of an abstract class or an interface or want to tweak an existing class definition. An object expression allows you to provide an implementation of a class or interface while at the same time creating a new instance of it. The syntax is similar to the alterative syntax for creating new instances of record types, with a few small alterations. You surround the definition of an object expression with braces. At the beginning is the name of the class or interfaces, and the name of a class must be followed by a pair of parentheses that can have any values passed to the constructor between them. Interface names need nothing after them, though both class names and interface names can have a type parameter following them, which must be surrounded by angled brackets. This is followed by the keyword with and the definition of the methods of the class or

interfaces being implemented These methods are separated by the keyword and, the name of the method must be the same as the name of a virtual or abstract method in the class or interface definition, and their parameters must be surrounded by parentheses and separated by commas, like NET methods must be (unless the method has one parameter, when you can get away with excluding the parentheses) Ordinarily you don t need to give type annotations, but if the base class contains several overall for a method, then you might have to give type annotations After the name of a method and its parameters comes an equals sign and then the implementation of the methods body, which is just an F# expression that must match the return value of the method #light open System open SystemCollections.

All the parts have been placed on the breadboard in Figure A-3. Most of the parts have long leads to start with, and you could insert them into the same holes without cutting them shorter, but you run the risk of accidentally touching the leads together, creating short circuits.

Up to now, all the examples in this book have been small and to the point, demonstrating one or two particular topics. The examples weren t particularly flashy, but they demonstrated an important piece of the Ajax puzzle. This chapter s example, known as the Ajax Dashboard, is a completely cross-browser application that mimics the Mac OS X Tiger Dashboard feature. While this example isn t nearly as polished as its parent, it does serve as proof that Ajax is easy to use and can provide a huge leap in usability. The Ajax Dashboard also serves as a demonstration test bed for the Taconite framework, so you ll see how much work the Taconite framework can save you. The full source code for the Ajax Dashboard is available from the Source Code section of the Apress Web site (www.apress.com). From there you can download the source and also the prebuilt WAR file that is ready to run in any modern servlet container such as Tomcat.