textbox text missing after detailsview postback?

[News User]

I have a imagebutton in a detailsview, which, when clicked, causes postback
and show or hide some of the rows. (Me.DetailsView1.Fields(4).Visible = true
or false) That's all it does.

In the same detailsview I have other controls : dropdownlist, checkbox and
textboxes etc., all of them are bound to database fields when page is
loaded.

When I changed the values in the dropdownlist/checkbox/textbox, and then
click the imagebutton to show/hide some other rows, all the changes I made
to the dropdownlist/checkbox/textbox are gone (restored to its original
bound value) after postback.

I commented the code that does the show/hide of rows, and found that the
values of dropdownlist/checkbox/textbox are preserved after postback.

So I wonder if this is normal -- when a row in a detailsview is dynamically
made shown or hidden, then the whole detailsview will have to be databound
again, causing all controls inside this detailsview to retored its original
bound value.

Thanks.

 

[News User]

I just found a workaround:
I had to save the updated information in ViewState, and then during
postback, assign the controls with the values saved in ViewState.

 

[Eliyahu Goldin]

It may help you, if you realize that web controls with Visible=false don't
get sent to the client and, naturally, don't bring their values back to
server on postbacks. If you are interested in hidden data either on client
or after postbacks, you should hide controls with css rule display:hidden
and leave Visible=true.