Open Specified Workbooks Only - excel

Question

I run this code daily that will affect each .xlsx workbook in the directory, but how can I ignore the workbook if the file name is not in the "Okay" array?
This is my current syntax:
Option Explicit
Public Sub OpenExcelInDir()
Dim MyFolder As String
Dim MyFile As String
MyFolder = "C:\ExcelSheets"
MyFile = Dir(MyFolder & "\*.xlsx")
Do While MyFile <> ""
Workbooks.Open Filename:=MyFolder & "\" & MyFile
MyFile = Dir
Call UpdateAllSheets
Loop
End Sub
Now I want to alter it so that I can declare a string array and only open the workbooks in the array something like so:
Dim goodWB() As String
goodWB= Split("ABC123,DEF456,GHI789", ",")

Answer 1

Even though I like the IsInArray function I think the algorithm is utterly inefficient. If you have 1000 files in that folder you will create 1000 temp arrays if one of the few given filenames match. Furthermore, I would expect that after opening one of the wanted files the code would not test against this name anymore (which is not the case).
Instead I propose to look at the problem from the other end:
Public Sub OpenExcelInDir()
Dim goodWB, filename
Dim MyFolder As String
Dim MyFile As String
goodWB = Array("ABC123.xls", "DEF456.xlsx", "GHI789.xlsx")
MyFolder = "C:\ExcelSheets"
For Each filename In goodWB
MyFile = MyFolder & "\" & filename
If Len(Dir(MyFile)) > 0 Then
Workbooks.Open filename:=MyFile
Call UpdateAllSheets
End If
Next WB
End Sub
Here, the Dir() function is used to test for the existance of the wanted filename in the specified folder. As an additional advantage there won't be any ambiguities like EEM mentioned in his/her comment.

Answer 2

I think this will do what you are asking for. I added a line to test if the file name matched one in the array.
Tested
Option Explicit
Public Sub OpenExcelInDir()
Dim goodWB() As String
goodWB = Split("ABC123.xlsx,DEF456.xlsx,GHI789.xlsx", ",")
Dim MyFolder As String
Dim MyFile As String
MyFolder = "C:\ExcelSheets"
MyFile = Dir(MyFolder & "\*.xlsx")
Do While MyFile <> ""
If IsInArray(MyFile, goodWB) Then
Workbooks.Open Filename:=MyFolder & "\" & MyFile
MyFile = Dir
Call UpdateAllSheets
End If
MyFile = Dir
Loop
End Sub
Function IsInArray(stringToBeFound As String, arr As Variant) As Boolean
IsInArray = (UBound(Filter(arr, stringToBeFound)) > -1)
End Function

Answer 3

Public Sub OpenExcelInDir()
Const kExt As String = ".xlsm" `As extension is fixed it could be defined as a constant to avoid repetition
Dim aWbks As Variant, vItm As Variant ‘Suggest to define the array in one step choose the form you prefer
‘aWbks = Array("ABC123", "DEF456", "GHI789")
aWbks = [{"ABC123", "DEF456", "GHI789"}]
Dim MyFolder As String
Dim MyFile As String
MyFolder = "C:\ExcelSheets"
MyFile = Dir(MyFolder & "\*" & kExt)
Do While MyFile <> ""
For Each vItm In aWbks
If vItm & kExt = MyFile Then
Workbooks.Open Filename:=MyFolder & "\" & MyFile
Call UpdateAllSheets
Exit For
End If: Next
MyFile = Dir
Loop
End Sub