ICanvas.DrawLine
ICanvas

procedure DrawLine(X0, Y0, X1, Y1: Integer);

Type Library
TeeChartx

Description
Draws line between end co-ordinates using current Pen. Does the same as Line method but it has been created to use it in VB and others environments that have Line word reserved.

Private Sub TChart1_OnAfterDraw()

TChart1.Canvas.DrawLine 0, 0, TChart1.Width, TChart1.Height

End Sub