Queries :: Pull Date Field From A Form

I have a query that is pulling a date from a Form. In my Query Criteria, I can put:

Code : >=[Forms]![frmAdhoc].[Date]
or
Code : <=[Forms]![frmAdhoc].[Date]
or
Code : =[Forms]![frmAdhoc].[Date]

And it works fine, but I don't want to hardcode the ">=", "<=" or "="

I would like the user to be able to choose ">=", "<=" or "=", from another field on the Form, so I am trying to code it on the query like this:

Code:
IIf([Forms]![frmAdhoc].[Variable]=">=",>=[Forms]![frmAdhoc].[Date],IIf([Forms]![frmAdhoc].[Variable]="<=",<=[Forms]![frmAdhoc].[Date],IIf([Forms]![frmAdhoc].[Variable]="=",[Forms]![frmAdhoc].[Date])))

But it isn't working for the ">=" or the "<=". It just gives me a blank result.