ArcObjects Library Reference (Editor)

IEditor.SelectionCount Property

[Visual Basic .NET]
Public ReadOnly Property SelectionCount As Integer

[C#]
public int SelectionCount {get;}

Available with ArcGIS Desktop.

This property returns the Map's total number of selected features belonging to editable layers.

[C#]

public void GetMapSelection()
{  
  //Get a reference to IApplication app in ICommand::OnCreate hook parameter.
  IEditor sEditor = app.FindExtensionByName("ESRI Object Editor") as IEditor;
  IEnumFeature enumFeature = sEditor.EditSelection;
  enumFeature.Reset();
  IFeature selFeature = enumFeature.Next();
  for (int fCount = 0; fCount < sEditor.SelectionCount; fCount++)
  { 
    IGeometry selGeometry = selFeature.Shape;
    'Code to do something with the geometry
     System.Windows.Forms.MessageBox.Show(selGeometry.GeometryType);
     selFeature = enumFeature.Next;
  }
}