Updating For Each loop variable - excel

Question

The aim is to find the circularity between value in column c and all values obtained from updated "firstvalue" variable which are comma separated and stored in column "M".
Sub circular()
Dim rng As Range, rng2 As Range, firstvalue As String, secondvalue As String
Set sh = ThisWorkbook.Worksheets("Sheet1")
lr = sh.Range("C" & Rows.Count).End(xlUp).Row
For Each rng In sh.Range("C5:C" & lr) 'iterating over each cell in column "c" from C5 till lastrow "lr".
firstvalue = rng.Offset(0, 10).value 'Corresponding cell value which is comma seperated in column
"M" i:e after 10 columns from "C".
Dim n As Variant
For Each n In Split(firstvalue, ",") 'Looping through each value obtained from split function.
Set rng2 = sh.Range("C5:C" & lr).Find(Trim(n), LookIn:=xlValues) 'Finding that split value again
in column "C".
If Not rng2 Is Nothing Then 'if exists in column c then get.
secondvalue = rng2.Offset(0, 10).value 'corresponding cell values.
firstvalue = firstvalue & "," & secondvalue 'now first value is concatnated
with initial firstvalue
End If
Next n
MsgBox firstvalue
'Now i want to itterate over updated "firstvalue" in split function and this goes on in circular
fashion until rng value exists in firstvalue.
Next rng 'then change next rng and continue the above whole process for this value and so on.
End Sub
This code is working for initial firstvalue, can any one suggest any method to iterate over updated first value.

Answer 1

I'm not sure if I understand your goal exactly, but this code should find all predecessors for each task:
Sub circular()
Dim sh As Worksheet
Dim rTask As Range
Dim oCell As Range
Dim oFound As Range
Dim lr As Long, j As Long
Dim aPredecessors As Variant
Dim sCurTask As String
Dim secondValue As String
Set sh = ThisWorkbook.Worksheets("Sheet1")
lr = sh.Range("C" & Rows.Count).End(xlUp).Row
Set rTask = sh.Range("C5:C" & lr)
For Each oCell In rTask
sCurTask = Trim(oCell.Text)
aPredecessors = getPredecessors(Trim(oCell.Offset(0, 10).Text))
j = LBound(aPredecessors)
Do Until j > UBound(aPredecessors)
secondValue = aPredecessors(j)
If sCurTask = secondValue Then
ReDim Preserve aPredecessors(j)
Debug.Print "Task '" & sCurTask & "': Cyclic link '" & secondValue & "' for '" & Join(aPredecessors, ",") & "'!"
aPredecessors(j) = aPredecessors(j) & " !!!"
Else
If secondValue <> vbNullString Then
Set oFound = rTask.Find(secondValue, LookIn:=xlValues)
If oFound Is Nothing Then
ReDim Preserve aPredecessors(j)
Debug.Print "Task '" & sCurTask & "': Task '" & secondValue & "' for '" & Join(aPredecessors, ",") & "' not found!"
aPredecessors(j) = aPredecessors(j) & " ???"
Else
Call addNewTasks(aPredecessors, Trim(oFound.Offset(0, 10).Text))
End If
End If
End If
j = j + 1
Loop
oCell.Offset(0, 11).Value = Join(aPredecessors, ",")
Next oCell
End Sub
Function getPredecessors(sPredecessors As String)
Dim i As Long
Dim aTemp As Variant, sRes As String
Dim sTest As String
sRes = vbNullString
aTemp = Split(sPredecessors, ",")
For i = LBound(aTemp) To UBound(aTemp)
sTest = Trim(aTemp(i))
If InStr("," & sRes & ",", "," & sTest & ",") = 0 Then sRes = sRes & sTest & ","
Next i
If Len(sRes) > 1 Then sRes = Left(sRes, Len(sRes) - 1)
getPredecessors = Split(sRes, ",")
End Function
Sub addNewTasks(aData As Variant, sPredecessors As String)
Dim i As Long, uB As Long
Dim aTemp As Variant
Dim sTest As String, sValid As String
aTemp = Split(sPredecessors, ",")
If UBound(aTemp) >= 0 Then ' Not empty
sValid = "," & Join(aData, ",") & ","
For i = LBound(aTemp) To UBound(aTemp)
sTest = Trim(aTemp(i))
If sTest <> vbNullString Then
If InStr(sValid, "," & sTest & ",") = 0 Then
uB = UBound(aData) + 1
ReDim Preserve aData(uB)
aData(uB) = sTest
sValid = "," & Join(aData, ",") & ","
End If
End If
Next i
End If
End Sub