i have a form in visual basic 2010

it contains 2 datepicker

the first one is the recharge date so i will choose the date
the second one is the expiry date so it will add automatically one month
(seconddatepicker = firstdatepicker + one month)

in the previous version of my app it was maded in access 2013
i put in the textbox control source (=DateAdd("m";1;[txt_Recharge_Date]))

but i can't use it in vb

any help please ??