Conditional .NET application settings.

Question

Dear ladies and sirs.

I have a client-server application, where there two options for the server - standalone executable or in another AppDomain in the client, which is very convenient for the debugging purposes. The choice of the server is transparent to the client, the only file that needs to be changed is the client app.config.

In order to switch from the standalone server to the local one, some sections need to be un-commented (like nhibernate configuration, which is only relevant to the server) along with individual settings (like authentication implementation, which is again only relevant to the server).

As of now, switching between the two modes is tedious and error prone, because one has to (un)comment several sections and individual settings.

Is there a way to specify conditional settings/sections in app.config? Or maybe there is a way to include another config file in the app.config? This way we could put all the local server specific settings in another file and only (un)comment its inclusion.

I would like to stress the fact, that I wish to have conditional sections, in addition to application settings.

Final note. The described scenario is obviously not for production. It is used exclusively for running unit tests. We use mstest for our unit tests.

Thanks.

Answer 1

One approach is to use build events. Create two application settings files each named according to the type of deployment. Create a new build configuration for each type of deployment.

Have a pre-build event that determines the type of build configuration that is being executed and then create the "app.config" file by copying the specialized config file and naming it "app.config".

Answer 2

In ASP.NET it is possible to have some settings in an external file (but I'm not sure if this is also available in windows apps):

Update: this also works for console/winforms applications.

web.config/app.config:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <!-- comment one of the following two lines -->

  <!--appSettings-->
  <appSettings file="YourSettings.config">

    <add key="KeyToOverride" value="Original" />
    <add key="KeyToNotOverride" value="Standard" />

  </appSettings>
</configuration>

YourSettings.config:

<appSettings>
  <add key="KeyToOverride" value="Overridden" />
  <add key="KeyToBeAdded" value="EntirelyNew" />
</appSettings>

Answer 3

nAnt may be another solution.

Answer 4

Add a new setting - AppType = Server/Standalone - duplicate each setting within App.Config that changes based on Server/Standalone so that there is just 1 app.config regardless of Server/Standalone. Move the conditional choices into your App.

if(AppType == ApplicationType.Server)
{
   Setup(NHibernate);
   Setup(Authentication Implementation);
}
else
{
   Setup(Standalone app stuff);
}

Answer 5

The app.config or web.config file can reference an external config file.

<configuration>
  <appSettings file="external.config">
  </appSettings>
</configuration>

MSDN appSettings reference

Answer 6

System.Configuration supports include files with configsource attribute. See here http://msdn.microsoft.com/en-us/library/system.configuration.sectioninformation.configsource.aspx or here http://rizwanshah.blogspot.com/2007/10/use-configsource-attribute-to-manage.html

You can use it like this:

<SomeSection configSource="myOtherFile.config" />

We've used to add differing sections to declarative wcf configuration etc/

Answer 7

Simple answer: Just use a command line argument. I am currently working on a project which needs to switch between 'local' (for testing / debugging purposes) and 'server' (when I deploy it to a production machine). I just have visual studio pass 'local' as a command line argument when I'm in debug mode, and use the presence of that argument to configure the software at runtime to do what I need it to do.

The absence of any argument causes the software to behave as if it's in production. When the software is ready for release, I'll just remove the argument logic entirely.

Answer 8

For your normal appSettings the norm would be to use this:

<appSettings file="appSettings.config" />

For other sections you can use

<mySection configSource="mySection.config" />

You have to have a file per section, and the configSource will only work with relative paths.

For your particular case, I would recommend a folder for each setup/configuration.

<mySection1 configSource="setup1\mySection1.config" />
<mySection2 configSource="setup1\mySection2.config" />

Then you can manually do a text 'find and replace' on the folder name to switch between setups, or run a batch file or build step that switches the folder on the file system (i.e. copy the setup1 folder to a currentSetup folder)

Note that you can't use a configSource on system.serviceModel, but you can for its subsections