How to avoid the Page Refresh when date selected time

Here is my code for select a date in Text box,when i select a date Adds the 5 days in the grid view label column below i am coloured the label,5 days adds correctly using TextChanged event, but one problem is every time the page is refresh how avoid if know share me!

 

Thank You

 

UpdateMode="Conditional" ChildrenAsTriggers="true">