I am looking at a compile error in buildpolist().  

When the second occurrence of "WhereStr=WhereStr" is used and following " AND ", the first WhereStr is selected and the error message "Expected: End of Statement"

How do I overcome this error?

Private Sub BuildPOList()

    Dim S As String
    Dim WhereStr As String
    
    S = "Select PurchaseOrderID, VendorName, PODate From PurchaseOrderQ"
    WhereStr = ""
    
    If ShowOpenPOs = True Then
        WhereStr = "IsOpen=true"
        ShowOpenPOsLabel.Caption = "Open POs"
    ElseIf ShowOpenPOs = False Then
        WhereStr = "IsOpen=false"
        ShowOpenPOsLabel.Caption = "Closed POs"
    Else
        ShowOpenPOsLabel.Caption = "Open && Closed POs"
    End If



    (Compile error occurs at the beginning of the second "WhereStr=WhereStr") (When the second "WhereStr=WhereStr" is
     omitted, as in the elseif statement, below, the error does not occur)


                                                            .................
                                                            Compile Error
                                                            Expected: end of
                                                            statement
                                                            .................
    If ShowReceivedPOs = True Then                          ________
        If WhereStr <> "" Then WhereStr = wherstr & " AND " WhereStr=WhereStr & "PartsReceived = True"
                                                            --------
                                                            _________________
                                                            .................
        ShowReceivedPOsLabel.Caption = "Received POs"
    ElseIf ShowReceivedPOs = False Then
        If WhereStr <> "" Then WhereStr = wherstr & " AND " & "PartsReceived = False" (I omitted the second use of WhereStr)
                                                                                      (and did not get the error in this statement)
        ShowReceivedPOsLabel.Caption = "UnReceived POs"
    Else
        ShowReceivedPOsLabel.Caption = "Received && Not"
    End If