crystal reports barcode font CHOOSING A PERFORMANCE OPTIMIZATION METHOD in .net C#

Embed QR in .net C# CHOOSING A PERFORMANCE OPTIMIZATION METHOD

Indexers allow you to expose the data contained by an object using array notation ([]). Arrays are described fully in 13. Indexers look a lot like properties, as you can see in Listing 8-13. Listing 8-13. An Indexer using System; class Product { private string[] productNames = new string[] { "orange", "apple", "pear", "banana", "cherry" }; public string this[int index] { get { return productNames[index]; } set { productNames[index] = value; } } } There are seven parts to the indexer in Listing 8-13, which is shown in bold. The parts are illustrated in Figure 8-2.

This code produces the following output:

); 1, 2, 3 ); 4, 5, 6, 7 ); 8, 9, 10, 11, 12 );

I ll start by discussing the simplest of the three methods. Here s the BeginEdit() method: Public Sub BeginEdit() CopyState(Me.EditLevel + 1) End Sub When the business or UI developer explicitly calls BeginEdit(), the object takes a snapshot of its state and cascades that call to its child objects. You ve already seen how this is done in the CopyState() method implemented in UndoableBase, and BeginEdit() relies on that preexisting behavior.

like what I have in Figure 16-5.

Note It is assumed that the environment variable (on UNIX) or registry setting (on Windows) named

incur another request to the server, the packet of information will be a lot smaller because you are just going to update part of the page; the entire page will not flash as it refreshes the user interface with the update. Beneath the resource tier comes the data retrieval tier. In a clean architecture, this is kept separate from the logic so that if data sources change, you do not need to get into the business logic plumbing and rip it out. It should provide a clean interface to the data layer. Visual Studio 2005 offers you the facility to create a proxy to an existing web service, which you can use to implement a data retrieval tier. In this application, the Price History web service from Yahoo provides CSV over HTTP so you will implement a web service that wraps this function, ality and can easily be proxied. The business logic tier is where you add value to your resources through aggregation, integration, and calculation. For example, in the case of calculating the P/E discussed earlier, with price information coming from one resource and earnings from another, instead of integrating and calculating these on the page level, you would aggregate the information in the business logic tier where the function performing the calculation would call the data retrieval tier to get the information from both resources and then perform the calculation. It would then provide the resultant information to the presentation tier as a response to the original request for the P/E analytic. The presentation tier is typically server-side logic that provides the markup and/or graphics that will get rendered in the browser. This can be anything from a C-based CGI service that generates raw HTML to an advanced control-based ASP .NET 2.0 server application. In this case, the example will use a variety of technologies, from ASP .NET controls that will render HTML that is generated by server-side C# code to advanced graphics functionality that renders the time series chart (you can see these charts in Figure 11-1). Finally, what appears to the user is the output of this presentation tier, and it is a document that contains HTML, graphics, JavaScript, style sheets, and anything else the browser needs to render. As I show how to construct the application, you ll see each of these tiers in a little more detail.