لطفا منتظر باشید ...
6.9. Deploy Your Application with ClickOnce
One of the driving forces behind the
adoption of browser-based applications is the fact that organizations
don't need to deploy their applications to the
client. Most companies are willing to accept the limitations of HTML
in order to avoid the considerable headaches of distributing
application updates to hundreds or thousands of users.
Note: Want the functionality of a rich client application with
the easy deployment of a web application? ClickOnce offers a new
solution for deploying your software.
Deploying a .NET client application will never be as straightforward
as updating a web site. However, .NET 2.0 includes a new technology
called ClickOnce that simplifies deployment dramatically.
6.9.1. How do I do that?
ClickOnce includes a few remarkable features: ClickOnce can automatically create a
setup program that you can distribute on a CD or launch over a
network or through a web page. This setup program can install
prerequisites and create the appropriate Start menu icons. ClickOnce can configure your
application to check for updates automatically every time it starts
(or periodically in the background). Depending on your preference,
you can give the user the option of downloading and running the new
updated version, or you can just install it by force.
ClickOnce can configure your application
to use an online-only mode. In this case, the user always runs the
latest version of your application from a web page URL. However, the
application itself is cached locally to improve performance.
ClickOnce is tightly integrated with Visual Studio 2005, which allows
you to deploy a ClickOnce application to a web site using the Project
Publish menu command.The following steps take you through the process of preparing yourproject for publication:Using Visual Studio 2005, create a new project. A good choice is a
Windows Forms application. Before continuing, save the project.Choose Build
Publish[ProjectName]
(or right-click your project in the Solution Explorer and choose
Publish). This launches the Publish wizard, which gives you a chance
to specify or change various settings.The first dialog page of the Publish wizard (the
"Where do you want to publish"
dialog) prompts you to choose the location where you will publish the
files to be deployed (see Figure 6-3). This
location is the file path or the virtual directory on your web server
where you want to deploy the application. For a simple test, use a
URL that starts with http://localhost/ (which
refers to the current computer). Click Next to continue.
Tip: When Visual Studio publishes the application, it will automatically
create a subdirectory named publish in the
current application directory, and it will map this to the virtual
directory path you've selected.
Figure 6-3. Choosing a deployment directory
Next, choose the install mode (see Figure 6-4) by clicking one of the buttons on the
"Will the application be available
offline" dialog page. Select "Yes,
this application is available online or offline."
This way, the setup will add application icons to the Start menu. If
you choose "No, this application is only available
online," the user will only be able to run it by
surfing to the virtual directory to which it's been
published. Click Next to continue.
Figure 6-4. Choosing the install mode
Finish to publish it. (You can publish an updated version at any time
by selecting Build
Publish
[ProjectName]
from the menu.)Once the wizard completes, the automatically generated ClickOnce web
page is launched, as shown in Figure 6-5. Using
this page, a user can click to download and install your application.
Try it out by clicking the Install
[AppName]
link.
Figure 6-5. The ClickOnce installation page
for user consent. For example, before the installation can add an
icon to the Start menu, it needs to prompt the user. Best of all, now that the application
is in place, you can make use of its automatic update ability. To
test this out, return to the application in Visual Studio .NET and
change the main form (perhaps by adding a new button). Then,
increment the version number of the application. (To do this,
double-click the My Project item in the Solution Explorer, select the
Application tab, and click the AssemblyInfo button. A dialog box will
appear that lets you set assembly metadata, including the version
number.) Finally, republish the application.When a new version is available on the server, client applications
will update themselves automatically, based on their update settings.
If you run the installed sample application, it checks for updates
when it starts. In this case, it will detect the new version and
prompt you to install the update.
Warning: The ClickOnce plumbing has been tweaked and refined continuously
during the beta cycle. In some builds of Visual Studio, you may
encounter an error when you try to publish a project using ClickOnce.
Unfortunately, there aren't any workarounds.
6.9.2. What about...
...computers that don't have the .NET Framework 2.0
installed? These machines can't download and install
a ClickOnce application automatically. However, when they surf to the
ClickOnce installation page, they will see a link that will install
the required prerequisites. There are a number of other approaches
you can pursue to get .NET 2.0 installed on the client ahead of time.
One easy choice is to use the Windows Update feature (surf to
http://windowsupdate.microsoft.com from the
client computer).
6.9.3. Where can I learn more?
There are a number of articles that discuss the ClickOnce technology
in much greater detail. For more information, you may want to refer
to the book
Essential
ClickOnce (Addison Wesley, forthcoming), or the
introduction from MSDN magazine at http://msdn.microsoft.com/msdnmag/issues/04/05/ClickOnce.
You can also find a great deal of information in the MSDN help
library, and online at http://msdn.microsoft.com/clickonce.
