Updating button field text

Question

hi All,

How can i update the  button feild  Text dynamically ??

for example :
<asp:ButtonField HeaderText="Activate Section" Text="Activate" Visible="false"  ButtonType="Button"  ControlStyle-CssClass="button" CommandName="btnActivate" />


now i want to change the text of this button feild to like say "Deactivate" for a selected row dynamically how can i do this?

thanx in advance