>You can start a trace in sql 2005 profiler and see the t-sql statement that executes the sproc you are interested in.

Vlad,

Thanks a lot.

@PersonType=N'-'

I see now that I'm passing '-' instead of 'N' as it supposed to.

I was suspecting this problem. Basically, I disabled ViewState for the combobox. It looks like when I pressed the Save button, the PostBack is occurring and therefore the Combo's value is reset to the first value in the list.

I guess I would have to leave the EnabledViewState to true and disable it in code by myself.

Or perhaps there is another way to solve my problem, because I don't want a full page refresh when I press the Cancel or Save button.

Or I can just try to set parameter's value in the code myself.