Combobox display from 1 table and selected value from another table

Question

Hi,

I have 2 forms: PreparationVoucher and MaintenanceVoucher

For PreparationVoucher :
I have 1 table VoucherType...
I am retrieving data in combobox from that table(Column name Description)
In column say values are: Chetan, Vaibhavi, Rohit, asha, shail, hiral, shalini.

Now  I select Vaibhavi in combobox and on button click I am throwing the data in other table  say VoucherMaster..

Now for MaintenanceVoucher(same form as PreparationVoucher):
What I want is in all column values shoul;d be there in combobox but Vaibhavi should be selected value on form load....