How to make a cell mandatory in sap.ui.table?

Hi,

I have used sap.ui.table with one label , 2 textbox and checkbox enable(using sapUiSizeCozy css) now i have a requirement like when a row is selected then the corresponding text box shld be mandatory... i didnt assign id to each cell.. instead i hav used a model variable to values for textbox.. how wil i get the value of textbox and assign validation(setvaluestate=error) when checkbox are selected and values in textbox is empty? onselection of checkbox how to retrieve values of textbox in the row??