Search a Subform

[libraccess]

I might be on the wrong track completely
I want to search a subform, of course the search only looks at the current form not all the records ever entered .


Soooo I have in the subform a search btn
Private Sub btnSearch_Click()
DoCmd.Close acForm, "frmMainDel", acSaveYes
DoCmd.OpenForm "frmSubDel", acNormal
End Sub
closes the form (and Sub) and opens the sub on its own with all the records
search works, I then have an exit btn under the search btn which is now visible False
Private Sub btnClose_Click()
DoCmd.Close acForm, "frmSubDel", acNormal
DoCmd.OpenForm "frmMainDel", acNormal
End Sub
which takes me back to the Main Form
The problem my first control in my sub is
Private Sub DateSub_LostFocus()
If Me.DateSub = "" Or IsNull(Me.DateSub) Then
MsgBox "Mandatory Field. A Delivery Date is Required.
Exit Sub
End If
End Sub
Of course when the Main Form is on a New Record this MsgBox pops up
How can I stop this or is there a better way?
Thanks

[June7]

Why do you need to do a search of subform full dataset? What do you do with the result of the search? Do you want to provide project for analysis? Follow instructions at bottom of my post.

[libraccess]

Ummm the DB is a bit big to post and is now in use. Staff member has used the Access search box on other apps and was puzzled as to why the search would not work. Ihave demonstrated how to drill down info in the report for these details and I hope that will do. Still it did seem quite handy one click (except for the msgbox if on a new rec) and there it is. Never mind thanks for your help