How to save changes to a web.config section?

[keithb]

How can an application change settings in the web.config file? I need to
allow users to configure SMTP email settings with functionality similar to
that provided developers by the ASP.NET Web Site Administration Tool. I
believe that I can get the settings using ConfigurationManager.GetSection,
but how can I save changes? If I do find a way to save changes, how can I
get IIS to read the file again so that the changes become immediately
available to the web site?

Thanks,

Keith

 

[Ken Cox - Microsoft MVP]

Hi Keith,

You're in luck because ASP.NET 2.0's Web Admin application does all this and
the source code is included. Take a look here:

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\ASP.NETWebAdminFiles\AppConfig

Also, check out the Save method here:

http://msdn2.microsoft.com/en-us/library/system.configuration.configuration.save(VS.80).aspx

Ken
Microsoft MVP [ASP.NET]


public void SaveConfig(Configuration config) {
RemotingManager.ShutdownTargetApplication();
config.NamespaceDeclared = true;

// check if session expired
if (String.IsNullOrEmpty(ApplicationPath) ||
String.IsNullOrEmpty((string)Session[APP_PHYSICAL_PATH])) {
Server.Transfer("~/home2.aspx");
}

config.Save(ConfigurationSaveMode.Minimal);
}

 

[Ken Cox - Microsoft MVP]

As for the second question, IIS resets the application as soon as there's a
change to the web.config.

Ken

 

[Erik Funkenbusch]

How can an application change settings in the web.config file?

There's lots of ways, such as simply reading and writing your changes via
file classes, to reading the file into a XMLDom object, making changes, and
saving it again.

However, you should be VERY careful about this, since changing the
web.config file will cause any currently running application (including the
one you're making the changes in) to reset, losing things like session
variables, authentication, the currently state, etc.. Basically, you will
dump the user out of the website entirely, as well as every other user
currently on the site.

If that's not what you want, then you might need to look at other ways of
storing your data that needs changing.

 

[Guest]

If you want your changes to be immediately available after being written
without having the web application restart on you, then you'll need to wite
them either to an xml file or preferably to a database.

You can have a method in your configuration class's code that automatically
re-reads the data from the database (or file) whenever a change is made.

IIS doesn't read web.config files - the ASP.NET runtime does.

Peter