If by dropdown you mean, an actual dropdownlist like the example below,
for performance reasons, i dont recommend this, nor will it be possible
to scroll down 5000 items.Depending on your webapp activity version, if
you are developing it using v5 activity, there is an object that allows
you to generate a table of rows containing records from the output of a
query, and the table data xpath allows you to configure this. In the new
version is all done through code here is an example.