VBA - Macro finish much faster when I click during the process - vba

Question

I have a macro with this loop which take a lot of time :
Dim tempval As String
Dim row As Integer, col As Integer
Application.ScreenUpdating = False
For row = 2 To 500 Step 1
tempval = ""
For col = 7 To 15 Step 1
tempval = tempval & Cells(row, col).Value
Cells(row, col).Value = ""
Next col
Cells(row, 7).Value = tempval
For col = 8 To 16 Step 1
tempval = tempval & Cells(row, col).Value
Cells(row, col).Value = ""
Next col
Cells(row, 8).Value = tempval
Next row
Application.ScreenUpdating = True
Range("LibAnglais2:LibAnglais9").Select
Selection.Delete Shift:=xlToLeft
Range("LibFrancais2:LibFrancais9").Select
Selection.Delete Shift:=xlToLeft
There is code, before, and after this loop.
With this loop, the code takes 3 minutes to end. Without, it takes 30s.
But when I click on the excel windows during the loop (You know when a program run, you click, the window become a white blur screen), my macro finish after I clicked and take approximately 45s...
Do you have an idea why ? And how can fix this to have a faster macro ?

Answer 1

Work with a variant array loaded in bulk directly from the worksheet. Use the Join Function for your concatenation (Chr(124) is the 'pipe' character) and return the processed values back to the worksheet en masse.
Option Explicit
Sub sonic()
Dim r As Long, vTMPs() As Variant, vVALs() As Variant
Application.ScreenUpdating = False
Application.EnableEvents = True
Application.Calculation = xlCalculationManual
With Worksheets("Sheet1")
vTMPs = .Range("G2:P500").Value2
ReDim vVALs(LBound(vTMPs, 1) To UBound(vTMPs, 1), LBound(vTMPs, 2) To 2)
For r = LBound(vVALs, 1) To UBound(vVALs, 1)
vVALs(r, 1) = Join(Array(vTMPs(r, 1), vTMPs(r, 2), vTMPs(r, 3), vTMPs(r, 4), _
vTMPs(r, 5), vTMPs(r, 6), vTMPs(r, 7), vTMPs(r, 8)), Chr(124))
vVALs(r, 2) = Join(Array(vTMPs(r, 2), vTMPs(r, 3), vTMPs(r, 4), vTMPs(r, 5), _
vTMPs(r, 6), vTMPs(r, 7), vTMPs(r, 8), vTMPs(r, 9)), Chr(124))
Next r
.Range("G2:P500").ClearContents
.Range("G2").Resize(UBound(vVALs, 1), UBound(vVALs, 2)) = vVALs
Application.ScreenUpdating = True
'I don't know what the following is supposed to do
.Range("LibAnglais2:LibAnglais9").Delete Shift:=xlToLeft
.Range("LibFrancais2:LibFrancais9").Delete Shift:=xlToLeft
End With
Application.EnableEvents = True
Application.Calculation = xlCalculationAutomatic
End Sub

Answer 2

Sometimes VBA needs to process messages to be faster. I don't really know why but if some of my macros act up like that I add a DoEvents line in the loop before the Next and it does wonders. It is not recommended for more complex applications. Here you can find a description of it: https://support.office.com/en-us/article/DoEvents-Function-7af41eca-88e0-470d-adaf-0b3d4c2575b0
So your code would be:
DoEvents
Next row
HTH

Answer 3

Ok guys, so, I found the solution.
In fact, I had a other sub in my code :
Private Sub Worksheet_Change(ByVal Target As Range)
And the code pass on this sub each time a cell was modified.
So I put a :
Application.EnableEvents = False
On my code, and it's work !
Thank's for your help !
EDIT : In fact, the problem is not totally solved... I noticed that the code take a lot of time after saving the worksheet or simply after modifiying the code... Do you have a solution ?