IIF problem in query criteria

[JosmithTwo]

This IIF works when the form has nothing in the txtVendor field BUT if a vendor is entered, I get nothing. I'm GUESSING that Access is interpreting the IIF with double quotes (i.e. "Like V12345") which it will never find. Suggestions?

SELECT IC_ITEM_REC.ITEM_NO, IC_ITEM_REC.ITEM_PRIME_VEND
FROM IC_ITEM_REC
WHERE (((IC_ITEM_REC.ITEM_PRIME_VEND) Like IIf([Forms]![frm_grossProfit]![txtVendor]>"  ",[Forms]![frm_grossProfit]![txtVendor],"*")));

[June7]

Why use the IIf?

Without IIf - if vendor entered, all records matching will return, if no vendor entered then ALL records are retrieved.

WHERE IC_ITEM_REC.ITEM_PRIME_VEND Like [Forms]![frm_grossProfit]![txtVendor] & "*"