ArcGIS Pro 2.6 API Reference Guide
QueryCoords Method (LineBuilder)
Example 

ArcGIS.Core.Geometry Namespace > LineBuilder Class : QueryCoords Method
The start point.
The end point.
Copies the endpoints of this line to startPt and endPt'. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public void QueryCoords( 
   out MapPoint startPt,
   out MapPoint endPt
)
Public Sub QueryCoords( _
   ByRef startPt As MapPoint, _
   ByRef endPt As MapPoint _
) 

Parameters

startPt
The start point.
endPt
The end point.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Remarks
Queries the startPt and endPt Points of the Line. These are the only parameters necessary to create a well-defined line.

Line Segment

Example
// Builder constructors need to run on the MCT.
ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
{
  // use the builder constructor
  using (LineBuilder lb = new LineBuilder(lineSegment))
  {
    // find the existing coordinates
    lb.QueryCoords(out startPt, out endPt);

    // or use 
    //startPt = lb.StartPoint;
    //endPt = lb.EndPoint;

    // update the coordinates
    lb.SetCoords(GeometryEngine.Instance.Move(startPt, 10, 10) as MapPoint, GeometryEngine.Instance.Move(endPt, -10, -10) as MapPoint);

    // or use 
    //lb.StartPoint = GeometryEngine.Instance.Move(startPt, 10, 10) as MapPoint;
    //lb.EndPoint = GeometryEngine.Instance.Move(endPt, -10, -10) as MapPoint;

    LineSegment anotherLineSegment = lb.ToSegment();
  }
});
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

LineBuilder Class
LineBuilder Members