Gets or sets the horizontal position of the LineMarker relative to the plot area. Its value range is (0, 1).If set this value,then the line marker's horizontal position is fixed. If the value is null or undefined and interaction is set to LineMarkerInteraction.Move or LineMarkerInteraction.Drag, the horizontal position of the marker is calculated automatically based on the pointer's position.

public double HorizontalPosition {get; set;}