so for two-way (bi-directional) databinding in ASP, we do this...
I've managed to find a work-around for my "edge-case".
I am using LLBLGen subtypes and therefore need to switch the datasource of the detailsview based on a radiobutton filter selected by the user.
I tried to bind to the sub type field "declaratively" in ASP using <%# Bind(... This did not work.
I had to resolve to a code-behind "hack" where I conditionally display the controls in the detailsview using details_view pre-render method.
For each field I then conditionally setup it's one-way (read-only) bind in OnDataBinding...
e.g. ((TextBox)sender).Text = Eval("FilePrefix").ToString();
Finaly to get the data to push into the datasource, I hack the DetailsView OnItemInserting/Updating events (conditionally as well)...
e.Values["FilePrefix"] = txtFilePrefix.Text;
I feel so dirty after this hack I think I need a shower...
I still hope someone can provide a cleaner approach :-)
Did you check out this page on MSDN, Walkthrough: Editing and Inserting Data in Web Pages with the DetailsView Web Server Control ?