private void LayerName() { IMxDocument pMxDoc = default(IMxDocument); IMap pMap = default(IMap); IFeatureLayer pFeatureLayer = default(IFeatureLayer); //Assign the mxDocument here..however you retrieved it...I usually use the snippet for retrieving the MxDoc from ArcMap pMxDoc = ThisDocument; pMap = pMxDoc.FocusMap; // Loop through each layer, and report its name. for (i = 1; i <= pMap.LayerCount; i++) { pFeatureLayer = pMap.Layer(i); Interaction.MsgBox("The name of layer is: " + pFeatureLayer.name); } }