DropDown

I have a dropdown and a textbox with in a grid.
if the selected value is 'No', the textbox should be disabled.
any idea as how to do the same

dropdown

Bind the textbox to the onSelectedIndexChanged property of the Dropdownlist and write a function for OnSelectedIndexChanged in the codebehind file.Include an if condition in the function to check whether the selected valuse is 'No', if it is ? then change the property of the textbox to be invisible.