excel data validation multiple selection within the same celle separated by comma - excel

Question

I have an excel spreadsheet where I need to insert a data validation from a list, so far not a problem but I need to be able to select multiple entries without overwriting the previous as the normal data validation so the final result would be this:
List
Data Validation Result
Mango
Apple, Mango, Pixel
Iphone
Pixel, Apple
Pixel
Apple
Apple, Mango
Mango
Apple, Mango, Pixel
Iphone
Pixel, Apple
Pixel
I have found online a VBA code to insert in my spreadsheet to obatin the multiple selection without repetion:
Private Sub Worksheet_Change(ByVal Target As Range)
'UpdatebyExtendoffice20180510
Dim I As Integer
Dim xRgVal As Range
Dim xStrNew As String
Dim xStrOld As String
Dim xFlag As Boolean
Dim xArr
On Error Resume Next
Set xRgVal = Cells.SpecialCells(xlCellTypeAllValidation)
If (Target.Count > 1) Or (xRgVal Is Nothing) Then Exit Sub
If Intersect(Target, xRgVal) Is Nothing Then Exit Sub
Application.EnableEvents = False
xFlag = True
xStrNew = " " & Target.Value & ","
Application.Undo
xStrOld = Target.Value
If InStr(1, xStrOld, xStrNew) = 0 Then
xStrNew = xStrNew & xStrOld & ""
Else
xStrNew = xStrOld
End If
Target.Value = xStrNew
Application.EnableEvents = True
End Sub
It kinda works but I have 2 problems:
I can select multiple choices from my data but the result is this
List
Data Validation Result
Mango
Apple, Mango, Pixel,
with the final comma
I cannot delete or empty the field if I make the wrong selection, I need to use the Erase all function on that cell and then use the dropdown function to re-extend the data validation field from the empty cells not completed so far
I'm not familiar with VBA so any help is appreciated.
I mainly use R and SQL this is a task that I need to do for another person in my office that is going to use this spreadsheet and need to use this function with the lowest difficulty.
Any suggestions?

Answer 1

I have modified the code to add the space and comma only if it actually needs to join 2 strings together. So the first value does not have a comma attached until a second value is also selected.
I have also modified it to allow cells to be cleared. Pressing Delete will now properly allow the user to clear a cell.
Private Sub Worksheet_Change(ByVal Target As Range)
'UpdatebyExtendoffice20180510
Dim I As Integer
Dim xRgVal As Range
Dim xStrNew As String
Dim xStrOld As String
Dim xFlag As Boolean
Dim xArr
On Error Resume Next
Set xRgVal = Cells.SpecialCells(xlCellTypeAllValidation)
If (Target.Count > 1) Or (xRgVal Is Nothing) Then Exit Sub
If Intersect(Target, xRgVal) Is Nothing Then Exit Sub
Application.EnableEvents = False
xFlag = True
xStrNew = Target.Value
Application.Undo
xStrOld = Target.Value
If xStrNew <> "" Then
If InStr(1, xStrOld, xStrNew) = 0 Then
xStrNew = xStrNew & IIf(xStrOld <> "", ", " & xStrOld, "")
Else
xStrNew = xStrOld
End If
End If
Target.Value = xStrNew
Application.EnableEvents = True
End Sub
I left it, in-case it is being used in code that was not copied to this post, but xArr & I are declared but not used. xFlag is declared and set True but not used in any expression.