Strange problem with Ajax

L

Lloyd Sheen

I have an app working and am now in process of cutting out viewstate and
adding javascript to speed up (less transfer) dropdown processing. I am
doing this by making use viewstate false and doing a __doPostBack with the
name of the control and the value passed as the selected value. This works
well and and should cut down on the traffic.


The first dropdown is a Genre list. It has an "All" setting which is set on
databound event of the ascx (it is a web control) and the other Genres are
bound at load (if not me.postback).

The second dropdown is a "FirstLetter". This dropdown is done in code in
the ascx file and has viewstate = true.

The third dropdown is a list of artists. This list is refreshed according
to the following:

If Genre change then if "All" I get all artist for the genre using the
current "FirstLetter" , enable the "FirstLetter" dropdown, and bind to the
third dropdown. Otherwise I get a list of artists for the particular genre
and disable the "FirstLetter" dropdown.

The first two dropdowns are in an update panel. All actions within the
panel are manual.

The last (third) dropdown is in its own update panel. All actions withing
the panel are manual. Only when there is a new list of artists is this
panel updated.

When I was using viewstate and events to capture the dropdown selections
there was no problem.

Now the problem.

Lets say fields are:
Genre: All
FirstLetter: A
Results show all artists with first name starting with A
Select an artist and in the content of the page (works so not part of the
problem) all is good.

Now fields are:
Genre: Classic Rock
FirstLetter Disabled (is A)
Results show all artists with genre Classic Rock (all first letters)
Select an artist and in the context of the page all is good.

Now Choose
Genre All
FirstLetter J
Results show all artist with first name starting with J
Select an artst and in the context of the page all is good

BUT

The list of artists has now reverted to "Loading Artists" as the only item.
This item is set on the ascx page to save load time and is only changed when
a Genre or artist is selected or on the first load. I have no idea how this
happens and can find no event or place to trace to find out how this is
getting reset. It is as if the web control is being reloaded except that
the list of Genres is complete.

I added an application error block but only see errors during the load.
What a useless event since there is no information in EventArgs and looking
at the trace shows no useful information.

Any ideas,
Thanks
Lloyd Sheen
 

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