Problem determine PickedPoint on selected object

[sieu khung khiep]

Hello, I have just stepped into .Net and I am currently having difficulty determining the point I have just chosen on the Object (here is the circle)
I have read this post and I use the class DisplacementJig  to move the circle:

https://www.keanw.com/2013/12/moving-text-in-an-autocad-block-using-net-part-2.html

the problem is that when I select the circle, the point I just selected [Promptpoint.Pickedpoint ] is not on the circle. so when I move the circle I won't get to the point I want
Can you guide me further?

 

thank you very much.

Edited November 6, 2019 by sieu khung khiep

[giskumar]

On 11/6/2019 at 1:27 PM, sieu khung khiep said:

the point I just selected [Promptpoint.Pickedpoint ] is not on the circle. so w

 

Picked point may not be always exactly on the selected object.

So the best way is to calculate the closest point to the selected object then use that point for movement.