Visual InterDev and Windows DNA

Visual InterDev 6 is part of Microsoft's Windows DNA (Distributed interNet Applications architecture). Windows DNA includes all the tools, servers, middleware, and database support required for building high-powered, integrated applications. Windows DNA is designed to address the various aspects of a distributed system such as a client/server or Web solution.

Visual InterDev is based on Microsoft's powerful Web application development framework, the Active Server framework, which enables Active Server scripting. Active Server scripting is script logic that is embedded in Web pages but that executes on the Web server instead of in the browser. Active Server scripting can be used to create Web applications with advanced server-side processing, including multitier Web applications that can use components developed in languages such as Visual Basic, Visual C++, and Visual J++. The use of server-side components also makes it easier to integrate internal legacy systems within an Internet or intranet solution while preserving all the benefits of Web technology—open standards, cost-effective deployment, cross-platform browsing, and low-bandwidth access. Finally, Visual InterDev includes integrated client-side scripting tools, and it is extensible by third-party components such as Java applets and ActiveX controls that can be added to Web pages and integrated using the Visual InterDev scripting tools.

Even though writing Active Server scripts with Visual InterDev is relatively easy, the scripts provide a powerful environment for Internet and intranet applications. For example, you can incorporate sophisticated functionality through Active Server components.

Active Server components provide the ability to process data and generate useful information, which extends the capabilities of the Web site. For example, using Visual InterDev, you can easily integrate server-side components written in Java, Visual Basic (4 or later), C, C++, or other languages that can create Component Object Model (COM) components. The Active Server framework allows these components to be tightly integrated into the Web application as either out-of-process components (EXEs), in-process components (DLLs), or remote components that leverage Distributed COM (DCOM) for multitier applications (remote EXEs). Server-side components can be limited to a page or globally accessible throughout an application so that a single instance can be shared by all users. Server-side components can also provide an effective way to integrate legacy systems directly into a Web application.

Active Server Pages

An ASP file consists of straight ASCII text in one or more of three forms: text, HTML, or script. An ASP Web page is an HTML page that contains server-side scripting. Server-side scripts are designated with an opening (<%) tag and a closing (%>) tag and are processed before the page is sent to the browser. The following code demonstrates a simple ASP Web page that contains server-side scripting and HTML.

 <HTML> <p> <%FOR  i=3 TO 7%> <FONT SIZE=<%=i%>> Hello World!<BR> </FONT> <% Next %> </HTML> 

In this example, a simple loop is performed to display Hello World! in an increasing font size within an HTML page.

When a user requests a URL with an ASP filename extension, the Active Server engine reads through the file from top to bottom, executing any commands and then sending pure HTML back to the user's browser.

Active Server scripting is completely integrated with HTML pages. To enable the Active Server engine to read a file, all you have to do is give the file an .asp file extension. Thus, you can change the extension of an existing HTML file from .htm to .asp to easily make it an ASP Web page. You can then make the HTML dynamic by adding Active Server script to the ASP pages. The host language of Active Server scripting is VBScript. However, you can use the <SCRIPT> tags to include scripts from other scripting languages, such as Perl and JScript.

Visual InterDev 6 enhances ASP by adding a server-side run-time library. This run-time library is implemented in JScript in the initial release of Visual InterDev 6. It is scheduled to move to a series of COM components in a future update to Visual InterDev.

The run-time library provides an object-based language interface. Design-time controls, which we'll discuss in the next section, are implemented by the run-time library and can be addressed as objects. The run-time library also makes it easy to do remote scripting from a browser to the server. This lets script in the browser call script functions on the server, which can improve the performance of your application.



Programming Microsoft Visual InterDev 6. 0
Programming Microsoft Visual InterDev 6.0
ISBN: 1572318147
EAN: 2147483647
Year: 2005
Pages: 143

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