Probe into the "longhorn" application development deployment (1)

Author: Dino Esposito translation: winsome zhong

In all respects, Microsoft's next-generation window is a very important milestone in the Windows product. "Longhorn" is the first operating system built with the hosted code, which uses Microsoft's latest storage subsystem "Winfs", supports a more advanced natural search technology (Natural UI) and the latest security architecture "Palladium", "Palladium", Windows history, I remember only two such important milestones, one is the migration of Windows from 16-bit to 32-bit, and the other is the birth of .NET. Of course, "Longhorn" is an exciting new feature that we have also shown that we will have a major change in the development method of driving (Oh, the resentment of the microsoft development technology and development tools is too many, but I complained that I believe that "Longhorn" new development model will definitely make you spiritual). One of these most important changes is "longhorn" to make the application can be encoded once, multiple scenes deploy. To implement this function, "longhorn"-based app is fully object-to-object, and the entire application is derived from a core object Application, which provides all core functions required to run the entire application. This article will lead you to experience the latest Longhorn application model and demonstrate some basic examples, including the classic "Hello World!".

First, the LONGHORN Application Model Application object is the core of the longhorn application model. Through its properties, methods, and events, you can use a enhanced HTML like a web page to write traditional Windows Forms applications. Application is the root object of a longhorn application. It provides the basic feature of the application, which can be used for some low-level, no programs that need to navigate and maintain status between forms, but more complex LONGHORN applications use NavigationApplication objects, which is an Application's subclass, added Support for navigation. A typical longhorn app can be seen as a page with a program script (called Page) and executed by the Application object control program. Page uses a new tag language to write, this tag language code is "Extensible Application Markup Language). Element tab by XAML You can control the layout of Page, including display text and images, insert buttons, text baskets, and other interactive controls. One words, "XAML" is a tag language for writing a Longhorn application UI interface. Of course, in addition to using XAML, you can also use program code to write applications. Generally, the longhorn program will use XAML and managed code at the same time. You can combine them in your own way. Using XAML and C # (or VB.NET), you can build various types of application output files, traditional EXE execution files, DLL libraries, or Console applications. Moreover, if your app is simple enough, you can also use a separate XAML tag to write it so that there is more types of programs in Longhorn. When the stand-alone XAML file does not quote other background classes, it can run directly in the longhorn shell and browsers. In fact, Longhorn's executable can run in Windows, or in the browser, you don't need any modifications to the code code, just set different item properties when compiling. For Longhorn, the executable is the next version of today's Windows Form Program. However, from another aspect, XAML and browser-based applications also represent an application as an innovation for the development model of the web client. Currently, Windows Forms client programs are rarely published on the web, because if you want to embed the Windows Form into your browser page, you will be subject to a lot of restrictions, but also modify the code. In Longhorn, the general application model allows you to write a program and deploy it through the web. However, this is a great difference with our traditional web applications (such as ASP.NET), which is the LONGHORN proprietary application. When you compile an app, the next version of "whidbey" will generate a .exe file, a list of files, a program file list (extension is .manifest and a deployment file list (extension is .deploy). When you click .exe file, the program will run in Windows as you expect. But if the program is set to run in the browser, IE will automatically jump out and run the program in it.

There is also an optional way to deploy the program on the remote server. The steps are as follows, first copy the .deploy file to the server's proper position, can be the relative path of FTP or HTTP. Then copy the compiled program file and .manifest to the server, the program file, the .manifest file is not necessarily to be put together with the.deploy file. If you put it in a different place, you can edit the .deploy file so that it points to the .manifest file. The .manifest file and .deploy file are XML files. When the user accesses the deployment file via the browser, Longhorn automatically downloads the program file and the .manifest file and install it on the user's computer, and create a shortcut to the.dePloy file. The user can execute the program by clicking the .deploy file. All universal structures for all Longhorn applications are: XAML Page couples program code (embedded or using code behind technology), root objects are derived from Application. The Application object is the controller of the program, its lifecycle, and the life cycle of the program. With Application objects, you can handle advanced events, shared code and status between PAGE, and more. It is also responsible for the logic of the procedure to make the user navigate in Page. When the user uses the software to complete the function, it will jump back and forth between Page. Longhorn will usually use the new Page to replace the old, of course, you can also choose A new window is popping up to display the new page. Navigation is not required for each program, simple only one page program is not required. Just mentioned that XAML Page can embed program code as a tag supplement. The program code is required, such as processing an event generated by the XAML element. The program code can be embedded in the XAML file or in the code file. LONGHORN's programming is based on managed code, but there are only several compatible .NET language that can be used to write XAML-based programs, including C #, VB.NET, and JScript.net, when you are published, other compatible .NET language It will also be included in it. It is currently only used in these three languages ​​because the source code of the XAML file needs to be compiled. Therefore, the compiler and related code document object model must be ready before (Note: If you complete the program code To write programs, you can use any .NET language, but XAML-based programs can only use these three more items). If the program code is embedded in XAML Page, you must compile it first to run it. And if there is no program code in XAML Page, you can display it, just like an HTML file. Longhorn does not execute uncharacted program code, nor does it compile it at runtime.

So let's take a look at Longhorn version of "Hello World!", This is the simplest XAML example: Hello, Longhorn! Save this code in a text file and use .xaml as an extension, then double-click, open it with your browser, Figure one is The result you can see. The node defines the user interface area of ​​the program - canvas. The Background property defines the background color of the canvas, Width and Height specify the size of the canvas, the , and elements define the contents of the Page. The LEFTs and TOP properties of these two elements specify their absolute positions relative to the upper left corner of the PAGE. Figure 1. Simple Xaml Page

Second, understanding that longhorn application Longhorn provides a range of frameworks, extended, and enhances the function of .NET Framework1.1, including support, application model, trusted computing and advanced web services for XAML and new storage subsystems. Wait. In Microsoft's plan, Longhorn and Whidbey represent two different milestones, which will release a few months before the Longhorn released, and will also release a WHIDBEY upgrade version to provide Longhorn's core services. Let's take a look at all public base of all longhorn applications - xaml language. XAML language is an XML-based language for describing programs user interfaces. Developers who are familiar with WIND32 or .NET Framework can immediately see the similarities of XAML and traditional Windows controls. However, the XAML tags are more abstract and extensive than the Wind32 control and Windows form controls. Think about the ASP.NET page, or, more specific, you can imagine a service-side control (Runat = "Server") ASP.NET page, which is a bit similar to XAML Page. Each XAML tag corresponds to one .NET framework class, including many methods, properties, events. You can set the properties directly to set the properties, write events, or you can do this in the Code-BEHIND code. In the program running period, the control corresponding to each tag is instantiated and the output is displayed in the canvas. From the highest level abstraction, this model is very like ASP.NET, but this model can work in a wider range of Windows platforms, not like ASP.NET is limited to Web programs. Each XAML tag corresponds to one .NET framework class, but there are many classes without a corresponding XAML tag, which is an abstract class for inheritance. Anything created with XAML can be created with program code, such as creating a button with XAML, you can use the following script: Click ME You can also create a touch button with the following C # code : Button btn = new button (); btn.width = new length (90); btn.height = new length (32); canvas.Settop (BTN, New Length (20)); Canvas.Setleft (btn, new length (75)); btn.content = "Click ME"; you can't use the method in XAML, but you can set attributes. Attributes in XAML corresponds to the Properties, but some Properties do not have corresponding Attributes, you can use the style table to set these Properties. Styles is a collection of Style Attributes, which automatically applies these styles to the controls associated with the style sheet.

All XAML Page has at least one Panel element, as a form container, and controls the position of the child control and background color, and the overall property of the font. The XAML element is a tree tissue, only one root node. In general, this root node is a PANEL, BORDER, or Canvas. The Canvas element is used to draw contents based on absolute coordinates. Generally, each element is drawn in different locations, but there may be two or more elements to be drawn on the same coordinates, and the order in which elements in the XAML file will determine their drawing order. In addition, XAML elements also support a large number of events, by creating an event processor, you can make your Page dynamically respond to various events. The method of creating an event processor for the XAML element is almost the same as the method in ASP.NET. The event processor is declared by an attribute,:

Click On Me // c # codebehind Class File: Events. XAML.CS

using System; using MSAvalon.Windows; using MSAvalon.Windows.Input; using MSAvalon.Windows.Controls; using MSAvalon.Windows.Documents; using MSAvalon.Windows.Navigation; using MSAvalon.Windows.Shapes; using MSAvalon.Windows.Data;

Namespace Application1 {public Partial Class Window1: Window {Private Bool Expanded = False;

private void OnLeftMouseDown (object sender, MouseButtonEventArgs e) {if (expanded) {sourceFlowPanel.Width = new Length (sourceFlowPanel.Width.Value / 2); sourceFlowPanel.Height = new Length (sourceFlowPanel.Height.Value / 2); caption. TextRange.Text = "Click on Me"; expanded = false;} else {sourceFlowPanel.Width = new Length (2 * sourceFlowPanel.Width.Value); sourceFlowPanel.Height = new Length (2 * sourceFlowPanel.Height.Value); caption .TextRange.text = "Thanks for clicking"; expanded = true;}}}} Figure 2 xaml plus procedural code

Compare XAML solutions and ASP.NET Web Form, which is difficult to find other obvious differences in addition to grammar. DEF: CodeBehind and DEF: Class Elements Specify how C # code methods and methods in ASP.NET are also very similar. But if you use a browser to open Events.xaml, the running period error shown in Figure 3 will appear. Fortunately, the error message is clear because XAML cannot be dynamically compiled. Unlike ASP.NET, the program code is embedded or referenced in the XAML script, and Longhorn requires the first to compile. This feature and may be modified in future versions, but in current, this forces you to use Visual Studio to manage and build project files for the Longhorn program, or one choice is to familiarize yourself with MSBuild tools. The extension of the longhorn program project file is consistent with the file structure and Visual Studio 2003, see Figure 4.

Figure 3 xaml error

<-! Imports the target which contains all the common targets -> <-! Application markup -> Figure 4 Longhorn Project File

Tag indicates the reference information of the project, the tab indicates the type of the package generated by the compiler. The properties of the project and Item are wrapped in the and tab. Elements have a good readability. You can use MSBuild in the command line to generate executables: msbuild.exe events.projmsbuild.exe in the .NET Framework directory: Windows / Microsoft .NET, but you don't have to pay too much attention to this tool, in the Whidbey version of Visual Studio In the middle, you can complete this thing as long as you click on the toolbar or press F5. Figure 5 shows the operation results of Figure 2 code. Do you only see a blue Panel and some text, is it too simple? In fact, it is slightly complicated than you see. The root node of this program tree is a DockPanel object, which is the outermost container of all UI elements, which includes a child, a FlowPanel, which is the container of the above text, and the text is actually an instance of the TEXT class. You should notice that there are some properties of the XAML tag to control their display, such as Width, Height, Background, and more. More importantly, they support ID attributes, IDs are used as the logo of the running period. When you press the mouse in any area in the FlowPanel control, and the FlowPanel associated MouseEleFTButTondNDown event will be triggered, and the event processor online is called, and the width and height of the FlowPanel in OnleFTMOUsedown are set to the original twice. Click on the mouse again, and FlowPanel is restored to the original size.

Figure 5 Running the app

Although you can also use program code such as C # to write your program, the description and template of the XAML file user interface have become simpler.

If you need to post, please indicate the author and the source.