I am trying to read StartingMonthColumn and CategoryHeadingColumn from the below app.config file using the code
ConfigurationSettings.AppSettings[\"StartingM
ConfigurationSettings.AppSettings is deprecated, see here:
http://msdn.microsoft.com/en-us/library/system.configuration.configurationsettings.appsettings.aspx
That said, it should still work.
Just a suggestion, but have you confirmed that your application configuration is the one your executable is using?
Try attaching a debugger and checking the following value:
AppDomain.CurrentDomain.SetupInformation.ConfigurationFile
And then opening the configuration file and verifying the section is there as you expected.