public static void SetSnapMode( 
   SnapMode mode,
   bool value
)

//ensure Midpoint snapping is switched on
Snapping.SetSnapMode(SnapMode.Midpoint, true);

// set only Point and Edge snapping modes, clear everything else
//At 2.x - ArcGIS.Desktop.Mapping.Snapping.SetSnapModes(SnapMode.Point, SnapMode.Edge);
ArcGIS.Desktop.Mapping.Snapping.SetSnapModes(
  new List<SnapMode>() { SnapMode.Point, SnapMode.Edge });

// clear all snap modes
//At 2.x - ArcGIS.Desktop.Mapping.Snapping.SetSnapModes();
ArcGIS.Desktop.Mapping.Snapping.SetSnapModes(null);


// set snap modes one at a time
ArcGIS.Desktop.Mapping.Snapping.SetSnapMode(SnapMode.Edge, true);
ArcGIS.Desktop.Mapping.Snapping.SetSnapMode(SnapMode.End, true);
ArcGIS.Desktop.Mapping.Snapping.SetSnapMode(SnapMode.Intersection, true);

// get current snap modes
var snapModes = ArcGIS.Desktop.Mapping.Snapping.SnapModes;

// get state of a specific snap mode
bool isOn = ArcGIS.Desktop.Mapping.Snapping.GetSnapMode(SnapMode.Vertex);