How to set Controls on TabItem to default values on Clicking on another TabItem in WPF

On windows load ,I am Binding data to datagrids in tabItem1 and tabItem2.

 the datagridheader has checkbox and row also have checkbox ,the functionality of checking and unchecking working fine.

Now after selection in TabItem1,if i click the TabItem2 and then go for TabItem1(the changes are same not showing defualt datagrid) How can i achieve this?

On tabitem change it should set the previous tabitem to default values. Im new in WPF

thanks in advance