Hi all.
Patience is a virtue!! Please read on!
I have a DetailsView that is bound to an ObjectDataSource (ods) whose
selectparameter is set when a row in a GridView is selected. Works fine. I
see the record in the DetailsView. In the DetailsView  i have a
templatefield named SystemCode with a DropDownList(ddlSystemCode) thats
bound to an ods (odsSystemCodes) and SelectedValue='Bind("SystemCode").
Works fine. I have another template field named TrainCode as a
CheckBoxList(cblTrainCode) that is bound to an ods (odsTrainCodes) and whose
SelectedValue='Bind("TrainCode"). When the user presses the Update Command
link, everything works fine. The ddlSystemCodes selected value is the one in
the database record. The TrainCodes CheckBoxList shows the correct checkbox
checked for the TrainCode in the database.

Now, in Edit Mode, if i select a different SystemCode from ddlSystemCode,
what i want to have happen is to have the TrainCode CheckBoxList show the
list of TrainCodes corresponding to the selected SystemCode.  I'm trying to
do this by putting code in the ddlSystemCode's SelectedIndexChanged event to
change the SystemCode Select Parameter of the TrainCode ods (odsTrainCode).
When i do this i get this error:
"DataBinding methods such as Eval(), XPath() and Bind() can only be used in
the context of a databound control".
Is it because of the SelectedValue='<%#Bind("Traincode")%>' in cblTrainCode
?
Any ideas, workarounds or better approaches  would be greatly appreciated!

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