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hroughout this book, you ve been exploring some of the underpinning technologies of ASP.NET AJAX, including the client-side JavaScript libraries, which are object-oriented additions to JavaScript. You ve also seen the power of ASP.NET AJAX server controls and the ease with which they can be used to add asynchronous update functionality to an ASP.NET page. In addition, we explored the rich set of UI controls and extenders offered as part of the ASP.NET AJAX Control Toolkit. Lastly, we reviewed the Virtual Earth SDK, and you saw how to add AJAX-style mapping functionality to your web applications. In this chapter, you ll go through, in detail, what it takes to build an application that makes the most of these features to deliver a real-world application. The application you will build is a very simple financial research tool that delivers stock quotes, extended stock information, and some price history analytics. This sort of information is typically used in technical analysis stock trading. Stock traders use a number of methodologies to determine a good buying or selling price of a stock, including fundamental analysis, where you look at company fundamentals such as dividends, profits, earnings per share, gross sales, and more usually a good methodology when investing in a company for medium- to long-term investments. Day traders, who are looking for a quick in and out, typically use technical analyses where they want to look at the momentum of the stock based on how it has performed in similar situations recently. The closing price for a stock over time is called the price history, and by applying various mathematical transforms to it, a day trader can guess where it is going to go. It s an inexact science, but when carefully applied, it can be effective. We will also use Bollinger band based analysis of price history and see how to deliver it in an ASP.NET AJAX application. You ll see how technical traders use this to determine potential times to get in and out of a stock. This should not be construed as investment advice; it is provided for informational use only and as a demonstration of the ASP.NET technology. You can see a snapshot of this application in Figure 10-1.

Elapsed times include waiting on following events: Event waited on Times ---------------------------------------Waited db file sequential read 2 SQL*Net message to client 2 SQL*Net message from client 2

In this chapter I introduced the concept of integrating applications using WCF and Windows Azure. WCF is a powerful tool for writing enterprise-class applications and makes loosely coupled applications easier to write and manage. Add to that the benefits of Windows Azure, and there are plenty of possibilities. A lot of the intricacies of WCF and Azure are beyond the scope of this book, so I simply showed you how to host a WCF service in the cloud. I demonstrated how other .NET applications (and even Java applications) will be able to take advantage of your cloud-based WCF services.

A method can return a value to the calling code. The returned value is inserted into the calling code at the position in the expression where the invocation occurred. To return a value, the method must declare a return type before the method name. If a method does not return a value, it must declare a return type of void. The following code shows two method declarations. The first returns a value of type int. The second does not return a value. Return type int GetHour() { ... } void DisplayHour() { ... } No value is returned. A method that declares a return type must return a value from the method by using the following form of the return statement, which includes an expression after the keyword return. Every path through the method must end with a return statement of this form. return Expression; Evaluates to a value of the return type // Return a value.

Figure 3-19. Consumption of resources while data binding The first hit you take on the web server s memory is when you call Fill on the DataAdpater. This marshals your entire result set from the database into the process space of the web server. The DataSet carries not only the current values as read from the database, but also the original values as the data was read out of the database, as well as metadata about the structure of the DataTable objects contained in its TablesCollection. The DataSet is a very powerful object, but it s also a very fat object. You take a hit whenever you load one into memory. If you re doing this on your home page, you re taking this hit not once, but once for each user that comes to your site. But wait, it gets worse. The next thing you do is set the DataSource of the DataGrid and call DataBind. As we just went over, this creates an in-memory collection of DataGridItems. This collection is probably just as large as your DataSet. If you re only outputting a couple of columns, maybe it won t be as large. If you re using a complex column template with a lot of markup, the size of this

So far, we ve explicitly specified the array types at the beginnings of all our array declarations. But, like other local variables, your arrays can also be implicitly typed. This means the following: When initializing an array, you can let the compiler infer the array s type from the type of the initializers. This is allowed as long as all the initializers can be implicitly converted to a single type. Just as with implicitly typed local variables, use the keyword var instead of the array type.

The preceding section showed the default Module1 and workflow code in VB .NET. This section will show the same code in C#. Because only the VB .NET projects were created in 1, the C# projects need to be created now. Create a new C# Sequential workflow console application called CFirstSequentialWFConsoleApplication, and create a new C# State Machine workflow console application called CFirstStateMachineWFConsoleApplication. Open the C# Sequential workflow console application just created. Open the Solution Explorer, and you ll see the file name is different. In VB, the code file for establishing the console application was Module1.vb, but within a C# application it s called Program.cs. First, open the Workflow1.cs file view the code, which follows: