Search for subform record based on text box

@Ken Sheridan Just realized it was because the Macros on the file were blocked and that is why it wasn't working, now it works! Thank you so much for the help!!

You can forward it to me at the following (munged) email address:

kenwsheridan<at>yahoo<dot>co<dot>uk

All subsequent correspondence will be via this forum.

All I can suggest is that you post your file, stripped of any personal or otherwise sensitive data, to a site such as Microsoft's OneDrive, and post the link in a reply here so that we can take a look at it.

@Ken Sheridan
Update - got it to work a bit more. Instead of having a button and the text box on the subform, I added a text box named HeaderSN and a search button on the parent form. The subform control in my case is the same as the name of the subform (Header Data Form). I used the code you used (see below), but now I am only getting data to fill in the fields in the parent form and not the subform. What am I missing here? Is this where the bookmark action would come into play? Why does the main form not need to be bookmarked but the subform does?

For future reference, is it possible to do this where the text box and/or the search button are on the subform instead of the parent form?

Private Sub Search_Header_SN_Record_Click()
Const MESSAGETEXT = "No matching records found."
Dim ctrl As Control
Dim strFilter As String

 Set ctrl = Me.[HeaderSN]  
    'HeaderSN is text field on parent form  
 strFilter = "[Furnace Run ID] IN(SELECT [Furnace Run ID] " & _  
     "FROM [Header Data] WHERE [Header SN] = """ & ctrl & """)"  
      
 If Nz(ctrl, 0) = 0 Then  
     ' turn off filter  
     Me.FilterOn = False  
     Me.[Header Data Form].Form.FilterOn = False  
 Else  
     If Not IsNull(DLookup("[Header SN]", "[Header Data]", "[Header SN] = '" & ctrl & "'")) Then  
         ' filter form to name selected in text box  
         Me.Filter = strFilter  
         Me.FilterOn = True  
              
         ' filter subform to selected Header SN  
         Me.[Header Data Form].Form.Filter = "[Header SN] = '" & ctrl & "'"  
         Me.[Header Data Form].Form.FilterOn = True  
     Else  
         ' inform user if no matching records found and show all records  
         MsgBox MESSAGETEXT, vbInformation, "Warning"  
         Me.FilterOn = False  
         Me.Requery  
         Me.[Header Data Form].Form.FilterOn = False  
     End If  
 End If  

End Sub

The reason for filtering the form rather than navigating to a specific record in my demo is that, in my case, there can be more than one parent record which matches the search criterion, so navigating to a record would just go to the first match. It makes more sense in that context to filter the form so that all of the matching records are together. In yours you could write the code to move the form to the first matching record, as there will be only one record which matches the criterion.

A subform control is a control in a parent form which houses the subform. The subform itself is the source object of the subform control. The control might or might not have the same name as the subform itself.

Where my code refers to ctrl this is an object variable. In my case it returns a reference to the ActiveControl because the code is in the combo box's AfterUpdate event procedure so the ActiveControl is the combo box. The default property of a control is its Value property, so when the code refers to ctrl without specifying any property of it, it is interpreted as a reference to the current value of the control, which in this case is the value of the ContactID field to which the combo box is bound, although the ContactID column is hidden and you see the contact's name from the second column of its RowSource. It would equally well work for a text box, though, because that will probably contain a string rather than a number, the value would need to be wrapped in literal quotes characters, e.g.

WHERE ContactName = """ & ctrl & """)"  

In this each literal quotes character is represented by a contiguous pair of quotes characters, "", which is how a quotes character can be included in a string itself delimited by quotes characters. Some people use a single quote character, ' instead, but that would not work with names like mine in its original non-anglicized form, Cináed O'Siridean, because it includes a single quote character as an apostrophe.

You are quite right, the IN operator does return a TRUE or FALSE value. ProjectID is the primary key of the parent form's table, so the expression will return TRUE if the ProjectID of a record in the Projects table has at least one match in the subform's ContactProjects table where the ContactID matches the value of the combo box. The record will thus be returned when the parent form is filtered. Where there is no match it will return FALSE, and then the record won't be returned.