How to disable a column in gridview inactive when adjucent dropdown selection had 'int'

Question

How to disable a column in gridview  inactive when adjucent dropdown selection  had 'int'?

i created gridview that contain serialNumber FieldName DataType & size

DataType is Dropdown list which contain

Int

varchar

char etc...

i want to deactivate size column if the DataType value is 'int'.

i need source code dear...