Choice approaches for passing a selected feature to a method in ArcObjects? (C#)

Question

It pains me to ask such a basic question, but after several hours (not exaggerating) of trying to figure this out and failing, I come to GIS.se

What I am trying to do is pass a selected feature and/or layer to a given method. In this example, it is to add a field to the selected layer in the ToC. The snippet calls for a feature class that is a member of the IFeatureClass interface (if my vocabulary is off, please correct me):

public void AddFieldToFeatureClass(IFeatureClass featureClass, IField field)

I create an IField easily enough:

IField statusField = new FieldClass();

But what is the preferred, cleanest, or most effective method to pass an IFeatureClass that is the currently selected layer in the TOC?

Answer 1

This works for me :

var fLayer = ArcMap.Document.CurrentContentsView.SelectedItem as IFeatureLayer;
if (fLayer != null)
    Debug.Print("got featurelayer");
else
    Debug.Print("no featurelayer selected (or maybe more than one is)");