Overwrite encrypted configuration section without decrypting?

Question

When I try to access configuration section that is encrypted and cannot be decrypted properly (for example, someone just grabbed config file from another machine blindly) - Configuration class is throwing an exception. I want to catch that situation and rewrite the section completely in such case.

I've tried to remove and add back the section in question, but it seems that removal is ignored - second statement in 'catch' throws another exception about such section already exists:

try
{
    // this getter might throw an exception - e.g. if encrypted on another machine
    var connStrings = config.ConnectionStrings;
}
catch (ConfigurationException)
{
    config.Sections.Remove("connectionStrings");
    config.Sections.Add("connectionStrings", new ConnectionStringsSection());
}

It might be related to the fact I have connectionStrings section residing in separate file, i.e. my config file has something like <connectionStrings configSource="connections.config"/>, while actual encrypted content is in the connections.config file.

Is it possible to do what I need without falling back to direct XML manipulations, by using .NET Configuration classes only?

Answer 1

I'm pretty sure this will do what you want. In my case, I just included a bogus connectionString setting:

<connectionStrings>
    <add connectionString="foo"/>
</connectionStrings>

I didn't include a "name" property, so trying to read ConnectionStrings will blow up, just like in your case:

try {
    var x = ConfigurationManager.ConnectionStrings;   //blows up             
}
catch {
    var config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
    config.Sections.Remove("connectionStrings");
    config.Save(); //Now save the changes
    ConfigurationManager.RefreshSection("connectionStrings"); //and reload the section
    var x = ConfigurationManager.ConnectionStrings; //can now read!                
}

You still won't be able to do this:

config.Sections.Add("connectionStrings", new ConnectionStringsSection());

Because (at least on my machine), it's picking up connectionStrings from the Machine.config.

I suspect though that in your case that's fine. You are now at a point where if you want to, you can add your own connection strings and you don't really need to completely blow away the connection string section.