Previous Data values are displaying in Edit popup

Question

Hi,

I am using Anjularjs and MVC 

In dynamically added rows i have 2 textboxes named as Category and Product

where category and Product are combo boxes

and also i have one grid view

In that i have one grid view 

based upon Id it can display the   relavant values on category and Product(Items)

Everything ois working fine

Probelm is that if i want to edit previous data in particular row 

It was displaying empty

 Ex:If OrderId=3 has 3 Items rows like below screenshot

https://ibb.co/1RK8yyp

After that if i try to edit row1 at that time it was displaying null like below

https://ibb.co/R9HP622 

Note:If i add new row at that time relevant values are displaying 

please look at below screen

https://ibb.co/hVZqjHX

So,finally my probelm is that only previous data values are not displaying in edit item row

Could kindly anyone help me