can you make args that are passed upon runtime in C# global?

I have an app that needs to set the connectionstring based upon an arg that is passed at runtime.  I would like to access that argument in any method to create the connectionstring instead of having to pass the value to every method as some methods have quite a few variables passed to it.  Since this value will be the same whereever it’s called, it can be set once and just be referenced when needed.

Does this make sense?