How to edit text in textbox on click of button in datalist

Question

I a using datalist in it I am using 1 button and 1 textbox.
How to edit text in text box on click of button?
My datalist code is:
<asp:DataList ID="datalist" RepeatDirection="Horizontal" RepeatColumns="6" AlternateText=" " runat="server" Height="102px" Width="229px" CellSpacing="5" >
<ItemTemplate >
<asp:TextBox ID="txt" runat="server" Text='<%# Eval("AName") %>' ReadOnly="true" Enabled="false" />
<asp:Button ID="edit" runat="server" Text="Edit" Height="30" Width="40" AlternateText=" " OnClick="edit_Click" CommandArgument='<%# Eval("AName") %>' CommandName="manageWiki" CausesValidation="True">

</asp:Button>
</ItemTemplate>
</asp:DataList>