Validation on DropDownList

Hi, I have a drop-down FreeList in my grid.web application, and I need to validate the data inside this cell in this way:

When the user type/paste a wrong value inside the drop-down freelist cell, the system must not erase the wrong value and mark the cell with red crosses, is this possible?

Or, if it is possible, to add a "hidden value" to free list options containing the "X.Gif" image.

Thanks in advance,


Please check the source code of the validation demo and check the different types of validations e.g., free list, dropdown etc. for your requirement:

Thank you.