I have a need for a simple combobox on a form in one of my programs that
represents city, state.  I want to have it autocomplete as the user types.
I have a table with these values (about 50k of them) and I'd like to source
it from there.

I have seen some methods out there for the autocomplete, but I think that
pulling 50k in the combobox might be too slow at runtime to build a table of
all those records and then bind the entire combobox to the 50k source.  It
is ok that they type a character or two and then it dynamically build a
combobox and start the autocomplete process.

What is the recommended method of doing something like this?  Is 50k records
for a combobox source excessive?  How have others gotten around this
efficiently?

Thanks,
Ben