Asp.Net Web Forms stops rendering value of <%#: Item %> for HTML control attribute once control is marked as run at server. Herewith snippet of Repeater ItemTemplate:
<a id="RepeaterElement" runat="server" href="?code=<%#: Item %>"><%#: Item %></a>
The resulting HTML code instead of href="?code=MyValue" becomes literally what it is behind the scenes href="?code=<%#: Item %>".
How can I manipulate with attributes of HTML control marked as run at server from .aspx file within Repeater Item?