具有一个无效的SelectedValue，因为它不存在于项列表中。你怎么调试？

I am having problems with asp.net binding to a dropdownlist and I have no clue on how to debug. I checked out the other questions about this on stack but nothing has helped. As far as I can see the "name" it should select is in the list. I am having problems with asp.net binding to a