protected bool FireSketchEvents {get; set;}

internal class ConstructionTool1 : MapTool
{
  public ConstructionTool1()
  {
    IsSketchTool = true;
    UseSnapping = true;
    // Select the type of construction tool you wish to implement.  
    // Make sure that the tool is correctly registered with the correct component category type in the daml 
    SketchType = SketchGeometryType.Line;
    //Gets or sets whether the sketch is for creating a feature and should use the CurrentTemplate.
    UsesCurrentTemplate = true;

    // set FireSketchEvents property to true
    FireSketchEvents = true;
  }

  //  ...
}