You want to use an App.Config.
When you add a new item to a project there is something called Applications Configuration file. Add that.
Then you add keys in the configuration/appsettings section
Like:
<configuration>
<appSettings>
<add key="MyKey" value="false"/>
Access the members by doing
System.Configuration.ConfigurationSettings.AppSettings["MyKey"];
This works in .NET 2 and above.