How to restrict block movement along a polyline ?

[Anonymous]

I need to allow user to place a block with text on top of a polyline. User can place block only along the line not anywhere else.

Kindly let me know if you need any further details. 

[Alfred.NESWADBA]

Hi,

using parametric/constraints would solve that without any development ...

- alfred -

[Anonymous]

Dear Alfred,

Thank you so much for your response .

But my requirement is to control  block movement programmatically in c#.net.I need  classes or methods in 

autocad dotnet api to add the constraints via code.

Thanks,

Raghu.

[norman.yuan · Accepted solution]

Since you are looking for code solution, one of my articles posted quite a while ago might be what you want, or at least gives some idea what/how the code can do:

https://drive-cad-with-code.blogspot.com/2012/03/moving-entity-along-curve.html