How to Add Geometry to an Existing Point Shapefile using C#

Hi every one. I need to add a Point Shape to an existing Point Shapefile to inherit all the attributes of existing Geometry Points in the Shapefile. Can any one help with this? I’ve tried all examples of CreatePointShapefile.cs, MarkPoints.cs, PoinIcons…none seem to be working. I must be doing something not right. Need help. Thanks in advance.

Running Mapwindow5, I am able to go to Edit Mode, and use the Add Geometry tool to add a new point on the Map. I get a pop up of all attribute fields of existing Points, and I am able to fill in data as required by the new point.
How can I achieve this in C# using the MapControl and AddShape tool, or cmNone?

Okay, so I do more research and I find this code - but still can’t add a Point! What am I missing?
priivate int _layerHandle = -1;

private void StartEditing()
axMap1.GrabProjectionFromData = true;

string filename = @"d:\data\sf\buildings.shp";
var sf = new Shapefile();
if (!sf.Open(filename))
    MessageBox.Show("Failed to open: " + filename);

_layerHandle = axMap1.AddLayer(sf, true);

sf.InteractiveEditing = true;
axMap1.CursorMode = tkCursorMode.cmAddShape;  // cmEditShape, etc
axMap1.ChooseLayer += axMap1_ChooseLayer;

// doing some edits interactively//sf.StopEditingShapes();


private void axMap1_ChooseLayer(object sender, AxMapWinGIS._DMapEvents_ChooseLayerEvent e)
if (axMap1.CursorMode == tkCursorMode.cmAddShape) // cmMoveShapes, etc
e.layerHandle = _layerHandle;