lookup

Hi All, Trying to adjust my code to a) When a user selects a value from the combo box in the data grid, it copies a value from a different column into another b) When the data grid refreshes, looks up each value and copies the look up values from a different column into another (for each row)...

In C# using Interop i am loading an excel which contains macros for validations and dropdowns for some columns. I use my logic to update the cells and save the excel.But once the excel is saved the macros validations are getting disabled and validations are not performing and also the lookups...