Currently I have a larger Solution with different projects (A web application and a windows service,...). Since both applications use the same database, I created a connectionstrings.config file which is included by the web.confg (or app.config) using the connectsionstring's configsource attribute.
To maintain only one file, I did the following:
To support different connectionstrings for different environments, I created environment folders that contain their own connectionstrings file. These files are used to replace the default ones during the buildprocess.
I wanted to know if you have other solutions for configuration values within different environments/projects?
If you are using Visual Studio 2010, you can use the config transform (video) feature.
See this blog post for details.