Blank cell contains a value when code is executed - excel

Question

I’m using a userform with 12 listboxes (numbered 2-13). Each list box could contain 0-8 items assigned by user from main listbox1. I run the following code to output the content of each list box (12 boxes) to sheet “Tray” when a button is pressed.
Each listbox is then output into corresponding columns of each tray from columns B-M. Listbox2 fills column 1 of each tray and so on. A maximum of 4 trays can be filled. The code checks the 1st well of each tray and if it contains a value it assumes the tray is full & begins filling the next tray.
Problem: If the first tray contains a blank column(listbox) and the second tray contains values in the same listbox, the code will fill blank column of the frist tray with values that should be in the second tray. Please see pictures below and updated code below:
Listboxes 2,3 and 4 for Tray 1 (note listbox3 is empty)
Listboxes 2,3 and 4 for tray 2 (note listbox3 has data)
Code ran two times: Listbox3 from tray2 appears in tray1 (erroneously!!!)
Expected output:
Sub Worklist()
'
Dim Var, VarName As Variant
Dim i, DblDashPos, FirstPeriodPos, lngColNum, lngRowNum As Long
Dim item As ListBox
Const cstrNames As String = "Listbox2,Listbox3,Listbox4,Listbox5,Listbox6,Listbox7,Listbox8,Listbox9,Listbox10,Listbox11,Listbox12,Listbox13"
Application.ScreenUpdating = False
lngColNum = 2
For Each VarName In Split(cstrNames, ",")
If UserForm2.Controls(VarName).ListIndex <> -1 Then 'if listbox is not blank
If Sheets("Tray").Cells(4, lngColNum).Value = 0 Then
'checks if value in row 3 column "lngColNum" is empty
lngRowNum = 4
ThisWorkbook.Sheets("Tray").Range("C2").Value = UserForm2.TextBox1.Value
ElseIf Sheets("Tray").Cells(15, lngColNum).Value = 0 Then 'checks if value in row 14 column "lngColNum" is empty
lngRowNum = 15
ThisWorkbook.Sheets("Tray").Range("C13").Value = UserForm2.TextBox1.Value
ElseIf Sheets("Tray").Cells(26, lngColNum).Value = 0 Then 'checks if value in row 14 column "lngColNum" is empty
lngRowNum = 26
ThisWorkbook.Sheets("Tray").Range("C24").Value = UserForm2.TextBox1.Value
Else 'otherwise assumes tray starts in row 5, column "lngColNum"
lngRowNum = 37
ThisWorkbook.Sheets("Tray").Range("C35").Value = UserForm2.TextBox1.Value
End If
For i = 0 To UserForm2.Controls(VarName).ListCount - 1
Var = UserForm2.Controls(VarName).List(i)
DblDashPos = InStr(1, Var, "--")
FirstPeriodPos = InStr(1, Var, ".")
Sheets("Tray").Select
ActiveSheet.Cells(lngRowNum, lngColNum) = Left(Var, DblDashPos - 1) & Right(Var, Len(Var) - FirstPeriodPos + 1)
lngRowNum = lngRowNum + 1
Next i
End If
lngColNum = lngColNum + 1
Next
Application.ScreenUpdating = True
End Sub
Thank you very much!

Answer 1

The problem is that you're only testing the column that corresponds to the ListBox to see if the cell is empty. If you want to test that all of the columns in a "tray" are empty, you need to test once for the entire sheet. Something like this (untested because I'm too lazy to rebuild your form):
Private Function FindFirstUnusedRow(sheet As Worksheet) As Long
Dim testColumn As Long, testRow As Long
Dim used As Boolean
For testRow = 4 To 37 Step 11
used = False
For testColumn = 2 To 13
If IsEmpty(sheet.Cells(testRow, testColumn)) = False Then
used = True
Exit For
End If
Next testColumn
If used = False Then
FindFirstUnusedRow = testRow
Exit For
End If
Next testRow
End Function
Then in your code, call it before your loop:
Sub Worklist()
Dim var As Variant
Dim i As Long, dashPos As Long, periodPos As Long, colNum As Long
Dim rowNum As Long, Dim sheet As Worksheet
Application.ScreenUpdating = False
Set sheet = ThisWorkbook.Sheets("Tray")
rowNum = FindFirstUnusedRow(sheet)
If rowNum = 0 Then
Debug.Print "All trays full."
Exit Sub
End If
Dim current As ListBox
For colNum = 2 To 13
Set current = UserForm2.Controls("Listbox" & colNum)
If current.ListIndex <> -1 Then 'if listbox is not blank
sheet.Cells(rowNum - 2, colNum).Value = UserForm2.TextBox1.Value
For i = 0 To current.ListCount - 1
var = current.List(i)
dashPos = InStr(1, var, "--")
periodPos = InStr(1, var, ".")
sheet.Cells(rowNum + i, colNum) = Left$(var, dashPos - 1) & _
Right$(var, Len(var) - periodPos + 1)
Next i
End If
Next colNum
Application.ScreenUpdating = True
End Sub
A couple other notes: You can ditch the Sheets("Tray").Select line entirely - you never use the selection object. Same thing with the mixed references to ActiveSheet and ThisWorkbook.Sheets("Tray"). Grab a reference and use it.
Also, these lines don't do what you think they do:
Dim Var, VarName As Variant
Dim i, DblDashPos, FirstPeriodPos, lngColNum, lngRowNum As Long
Of all the variables you declare, everything is a Variant except lngRowNum. If you want to combine declarations on one line like that, you still need to specify a type for each variable, or they'll default to Variant. See the example code above.