How to bind/eval a field only for inserting/writing?

Question

I got the difference between Bind and EVal from here. Bind will do both way reading and writing. And Eval do only reading. So any function only for writing?

Answer 1

Actually no.

However...

Some databound controls, such as the ListView, support binding in the InsertItemTemplate. The insert item template of the ListView only writes. Although the binding is only actually used for writing, you still use Bind() syntax.

On a related note:

For ther data bound controls, such as the GridView, I've had to bootstrap empty dummy data into a row of the data source and tap into the RowDataBound event to toggle visibility on my insert and edit command buttons. The read phase of the bind reads dummy data, and the write phase binds values I can use in an insert statement. It is not nearly not as elegant a solution as using the InsertItemTemplate support provided by the ListView.