Please try item(“E Code”).ToString or item(“E.Code”).ToString in the assign activity.
You post title says “E Code” but your screenshot shows “E.Code”, so pass the correct column name.
If you are trying to get the value from a particular column in a datatable, then you can do it in 2 ways. You can use
For each row in datatable activity
1)Using column name. row(“E Code”).ToString
2)using index. row(1).ToString. if column E Code is the second column in datatable.