Charitable contribution--purchased all the wine for a charitable event and have itemized receipt--do I enter as cash donations or items? If items, what category?

Since you spent the money so the charitable organization would not have to, and immediately transferred the purchase to the organization for use at the event, I would consider this to be a cash contribution.

Be certain to obtain a signed, detailed receipt for the wine (vintner, variety, year, number of bottles/cases, value) from the recipient organization and keep that receipt and your purchase receipt with your tax records for the year.

Further information about charitable contributions can be found here: IRS Pub. 526 Charitable Contributions.

This is an unreimbursed expense donation.  A receipt from the charitable organization acknowledging the item donated is recommended.  It's also required for deductability if it is over a certain $amount.  It won't make much difference if you categorize it as a cash or as an item donation since the value will be the same.