VBA Infinite loop - When no value is enetered by the user - vba

Question

I'm a newbie to VBA and I'm writing a VBA code that will accept user inputs for the serial numbers for the Start and End value and will check if the serial numbers in another sheet fall between the range specified. If it does, then my code will pick the complete record and paste it into another sheet.
Now, the challenging part is that the serial number value isn't consistent and it could be alpha-numeric string with no fixed length. So, I've used StrComp function to check if the value lies in the range specified by the user. The problem is if the user types in a value for start value and end value that doesn't exist in the sheet of serial numbers then it goes on an infinite loop.
For instance, if there is a serial number say 1120 and the user enters 1110(which doesn't exist) for start value and 1200 for end value, the code goes on a infinite loop. Technically, the code should pick the serial number 1120 and return since it does lie in the range 1110 and 1200 eventhough the value 1110 doesn't exist in the sheet.
Here is my code:
'Assigining values enterted by user to variables
start = Me.txtStart.Value
finish = Me.txtEnd.Value
'Checking Upper bound Vs Lower bound
If (Len(start) <> 0 And (Len(finish) <> 0)) Then
If (StrComp(start, finish) > 0) Then
MsgBox ("Lower Bound cannot be higher than the Upper Bound")
Exit Sub
Else
If Len(tempWorkPriority) = 0 Then
MsgBox ("Enter a value for Work Priority")
Exit Sub
Else
If Len(tempDescription) = 0 Then
MsgBox ("Enter a value for Description")
Exit Sub
Else
Goto Here
End If
End If
End If
Else
result = MsgBox("Please enter values for Upper and Lower bounds")
Exit Sub
End If
End Sub
Here:
Sheets("Imported e-Facilities Data").Activate
'Number of rows in Raw Data sheet
RowCount = Cells(Cells.Rows.Count, "A").End(xlUp).Row
'Loop to iterate and pick data that falls within the specified range
For i = 2 To RowCount
tempSerial = Range("A" & i).Value
tempAsset = Range("V" & i).Value
tempAssignedResource = Range("R" & i).Value
tempManufacturer = Range("F" & i).Value
'Condition to check if a Serial Number falls within the range
If (StrComp(start, tempSerial) <= 0 And StrComp(tempSerial, finish) <= 0) Then
'Selecting Export Sheet
Sheets("Data Ready for Import").Select
'Counting Rows in the Export sheet
RowCountExport = Cells(Cells.Rows.Count, "A").End(xlUp).Row
Range("A" & RowCountExport + 1).Value = tempSerial
End If
Next
End Sub
Please Help!!!

Answer 1

You're using unqualified calls to Range so you are relying on the active sheet being set correctly. When you find a serial number which falls within the range, you call Select on a different sheet which has the effect of changing the active sheet. The next time round your loop tempSerial, tempAsset etc will be read from the "Data Ready For Import" sheet which is now active rather than the "Imported e-Facilities Data" sheet which was being used before.
You should qualify your Range references instead of relying on the active sheet, Select or Activate:
Set wsInput = Worksheets("Imported e-Facilities Data")
tempSerial = wsInput.Range("A" & i).Value
or use With ... End With for repeated references to the same object:
Set wsInput = Worksheets("Imported e-Facilities Data")
With wsInput
tempSerial = .Range("A" & i).Value
tempAsset = .Range("V" & i).Value
tempAssignedResource = .Range("R" & i).Value
tempManufacturer = .Range("F" & i).Value
End With