Web.Config Transformations when Debugging

I am a big fan of the Web.Config Transformations that got introduced a while back. Prior to them being inherently supported, one could accomplish the same thing with part of the Enterprise Library, and prior to that, one could leverage a custom MSBuild Task or the XMLPoke Task to get your web.config updated based on the environment it was targeting.

Having your configuration elements managed with a transform file makes it a bit easier to manage and keep track of your settings that could change based on environment or settings. Without this, each developer on your team might need to create host entries and keep their folder structure the same to ensure the settings work for each of their machines. Another option is each team member just has their own configuration files with their specific settings that they need but when source control is introduced, this can get tricky because one developer might be overwriting another's settings.

Unfortunately, VS.Net doesn't do any transforming when you are developing and just debugging your local environment. But there are some steps you can do to make this happen if you want.

• First, create the configurations you want in VS.Net, assuming the default debug and release are not enough for what you are trying to accomplish.
• Right click on you web.config and select Add Config Transforms - this will create a dependant transformation config for each of your configurations defined.
• Now you can rename your web.config to web.base.config.
• Add a web.config to your project. It doesn't matter what is in it because it will get overwritten every time we do a build but we want it as part of the project so VS.Net doesn't give us the "Your Project isn't configured for Debugging" pop-up.
• Edit your .csproj Project File and add the following TransformXml task to the AfterBuild target. Here, you can see that I will be transforming the web.base.config file using the web.[configuration].config and it will save it as web.config.

For aesthetics, I renamed my transformation files to just web.[configuration].config instead of web.base.[configuration].config and updated the project file like below:

So the transformation files are nested under the web.base.config and the web.config doesn't have any transformation files because it is the output not the input. Below, you can see the setup I have so far for the Ergo project where my web.config would look quite different depending on whether I am using Ektron or NHibernate as my data repository.