Question

Is it is possible to do something like the following in the app.config or web.config files?

<appSettings>  <add key='MyBaseDir' value='C:\MyBase' />  <add key='Dir1' value='[MyBaseDir]\Dir1'/>  <add key='Dir2' value='[MyBaseDir]\Dir2'/> </appSettings> 

I then want to access Dir2 in my code by simply saying:

 ConfigurationManager.AppSettings['Dir2'] 

This will help me when I install my application in different servers and locations wherein I will only have to change ONE entry in my entire app.config. (I know I can manage all the concatenation in code, but I prefer it this way).

Answer 1

Good question.

I don’t think there is. I believe it would have been quite well known if there was an easy way, and I see that Microsoft is creating a mechanism in Visual Studio 2010 for deploying different configuration files for deployment and test.

With that said, however; I have found that you in the ConnectionStrings section have a kind of placeholder called ‘|DataDirectory|’. Maybe you could have a look at what’s at work there…

Here’s a piece from machine.config showing it:

 <connectionStrings>     <add         name='LocalSqlServer'         connectionString='data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true'         providerName='System.Data.SqlClient'     />  </connectionStrings>