How to prevent entering duplicate

This is what validations are made for.

docs.appian.com/.../recipe-add-validations-to-an-inline-editable-grid.html

Thanks Stefan, 

But we have non editable grid aready implement and need to to apply such validation.

So you do NOT edit the data directly in the grid?

Then, validations are still the way to go. You just need to implement the logic to detect duplicates and use that on the input fields.

Yes, when we click on edit then for duplicates we are displaying message and disables the submit button. But the same functionality working for current edited value and it dies not allow the user to approve through the button as it gets disabled.

I think I am missing something here ?!?!?

Can you explain in more detail and post some screenshots?

You seem to have some logic which works in one case, but not in another. Without more details I will not be able to support you.

I think both Stefan and I are pretty unclear what your actual use case is.  I suggest starting at the beginning and giving us a step-by-step description of what you would expect the user experience to be, including which of those expectations you're currently unable to meet.  By that I mean you should write it out step-by-step giving details, instead of a vague overview that requires us to just guess at what you're really after.

I think both Stefan and I are pretty unclear what your actual use case is.  I suggest starting at the beginning and giving us a step-by-step description of what you would expect the user experience to be, including which of those expectations you're currently unable to meet.  By that I mean you should write it out step-by-step giving details, instead of a vague overview that requires us to just guess at what you're really after.