HI..
IMapLayer its a layer which linked with map, and can be FeatureLayer, RasterLayer etc..
IFeatureLayer its a layer with point, line or polygon features, and may be not linked with any map.
IMapFeatureLayer its IFeatureLayer linked with map, and have properties and methods from both.
if layer linked with map, its have symbology, labels, legendtext etc..
When use which interface depends from your task.
P.S. Sorry from my English.. I from Ukraine..
IMapLayer its a layer which linked with map, and can be FeatureLayer, RasterLayer etc..
IFeatureLayer its a layer with point, line or polygon features, and may be not linked with any map.
IMapFeatureLayer its IFeatureLayer linked with map, and have properties and methods from both.
if layer linked with map, its have symbology, labels, legendtext etc..
When use which interface depends from your task.
P.S. Sorry from my English.. I from Ukraine..