Using VBA regex on Array - regex

Question

I am writing a macro and the macro works fine, but I am trying to add some error handling to it so others are using it and an error occurs they are able to figure out what happened. The last problem I am having is I am using the Application.GetOpenFilename to open multiple files with multiselect = True. I am using a regex to match the file name and if the wrong file name is chosen then it displays an error message. If multiselect = False then I get no errors, but when it is equal to True I get a Type Mismatch error. I can only assume this is because when mutliselect = True the file is an array which the regex cannot handle. Is there a solution to this or can anyone point me to a better solution to handle the error. I have attached the VBA script as well.
Sub DataImport_Loop()
Dim nom As String
Dim wb As Excel.Workbook
Dim i, j, k, m, n, file As Variant
Dim strPattern As String: strPattern = "Strain End Point [0-9] - FEA Loop - Loading - (Timed)" 'File Pattern
Dim regex As Object
Set regex = CreateObject("VBScript.RegExp")
'Turns Screen Updating and Alert Displays off
Application.ScreenUpdating = False
Application.DisplayAlerts = False
nom = ActiveWorkbook.Name
'takes user straight into necessary folder
If CurDir() <> CurDir("J:") Then
ChDrive "J:"
ChDir "J:FEA Material Data"
End If
'Number of specimens tested
For i = 1 To 5
'Allows user to select multiple files to open
file = Application.GetOpenFilename( _
FileFilter:="Text Files (*.csv), *.csv", _
MultiSelect:=True)
'If no file selected, stop data import and display error message
If Not IsArray(file) Then
MsgBox ("You only imported " & (i - 1) & " Specimens.")
Exit Sub
'Sets patteren to check if correct file
With regex
.Pattern = strPattern
End With
'Checks set pattern, displays error message if not correct file
If regex.Test(file) = False Then
MsgBox ("Select Loading Only")
Exit Sub
End If
Else
Counter = 1
While Counter <= UBound(file)
j = (2 * i) - 1
Workbooks.Open file(Counter)
Set wb = Workbooks("Strain End Point " & Counter & " - FEA Loop - Loading - (Timed).csv")
'End of column, needs + 3 to account for first 3 unused cells
k = Range("F4", Range("F4").End(xlDown)).Count + 3
'Loops through data, deletes negative values
For m = 4 To k
If Range("F" & m).value < 0 Or Range("F" & m).Offset(0, 1) < 0 Then
Range("F" & m).Delete
Range("F" & m).Offset(0, 1).Delete
'If cell is deleted, rechecks new value
m = m - 1
End If
Next m
Range("F4:G" & k).Copy
Workbooks(nom).Sheets(Counter + 1).Cells(4, j).PasteSpecial
wb.Close
'Opens next file
Counter = Counter + 1
Wend
End If
Next i
'Turns Screen Updating and Alert Displays back on
Application.DisplayAlerts = True
Application.ScreenUpdating = True
End Sub

Answer 1

When MultiSelect is true, file will always be a variant array, even if only a single file is selected. Therefore you must iterate through each element of the array in order to check it against your mask.
With regard to your mask, I would suggest using the Like operator as it seems simpler and will probably run faster. Note the # replacing the regex pattern [0-9]) eg:
'Checks set pattern, displays error message if not correct file
Const strPattern as String = "Strain End Point # - FEA Loop - Loading - (Timed)" 'File Pattern
For I = LBound(file) To UBound(file)
If Not file(I) Like strPattern Then
MsgBox ("Select Loading Only")
Exit Sub
End If
Next I