Can I Add ConnectionStrings to the ConnectionStringCollection at Runtime?

Question

Is there a way where I can add a connection string to the ConnectionStringCollection returned by the ConfigurationManager at runtime in an Asp.Net application?

I have tried the following but am told that the configuration file is readonly.

ConfigurationManager.ConnectionStrings.Add(new ConnectionStringSettings(params));

Is there another way to do this at runtime? I know at design time I can add a connection string to the web.config; however, I'm looking to add something to that collection at run time.

Thanks

EDIT: One of the reasons why I'm attempting to do this is due to a security requirement that prevents me from placing ConnectionStrings in the web.config (even encrypted). I would like to use elements like Membership and Profiles on my project; however, I am looking into an alternative to doing such w/o writing a custom provider. Custom Provider's aren't all that bad, but if I can find an easier solution, I'm all for it.

Answer 1

You can use reflection to disable the private bReadOnly field (bad idea, etc.):

typeof(ConfigurationElementCollection)
    .GetField("bReadOnly", BindingFlags.Instance | BindingFlags.NonPublic)
    .SetValue(ConfigurationManager.ConnectionStrings, false);
ConfigurationManager.ConnectionStrings.Add(new ConnectionStringSettings());

This is similar to the technique required to modify an existing connection string, and added as a comment there by Brian Rodgers.

Answer 2

var cfg = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration(@"/");
cfg.ConnectionStrings.ConnectionStrings.Add(new ConnectionStringSettings(params));

cfg.Save();

Be Advised this will cause your website to recycle since it modifies the config file. Check out http://msdn.microsoft.com/en-us/library/4c2kcht0(VS.80).aspx