The configuration element is not declared

Question

I\'m doing some work in Visual Studio 2012 Express Edition. I have added an App.config XML file as follows:

Answer 1

Visual Studio 2013 Express Edition is missing the DotNetConfig.xsd (https://connect.microsoft.com/VisualStudio/feedback/details/817322/dotnetconfig-xsd-files-not-present-in-vs-2013-express-for-desktop).

So to get rid of the warning in VS 2013 Express:

• get a copy of DotNetConfig.xsd from another system or from the web (I used https://gist.github.com/eed3si9n/5dd7dd98ad2b3f668928b23477de35a3)
• download to C:\Program Files (x86)\Microsoft Visual Studio 12.0\Xml\Schemas
• add the schema following Ramakrishna's answer

The warning should be gone.