Excel VBA Open xlsx File From Folder Without writing Path - vba

Question

I want to open Excel xlsx file without writing path by using variables. I din't know why but it is not working. I have a folder with the main workbook and another one that I want to open that is xlsx. I want to name it UnionWB.
Private Sub cmdStartMonth_Click()
'Optimize Macro Speed
Application.ScreenUpdating = False
Application.EnableEvents = False
'Analyze month by selecting
Dim myPath As String
Dim myFile As String
Dim UnionWB As Workbook
Dim MonthName As String
MonthName = ListMonth.Value
myExtension = "*.xlsx*"
Set UnionWB = Workbooks.Open(ThisWorkbook.Path & myExtension)
Application.ScreenUpdating = True
Application.EnableEvents = True
End Sub
Set UnionWB = Workbooks.Open(ThisWorkbook.Path & myExtension)

Answer 1

Here's a couple of examples that may help.
The first will ask you to select the correct file and then open it:
Public Sub Test()
Dim sWrkbkPath As String
Dim UnionWB As Workbook
sWrkbkPath = GetFile(ThisWorkbook.Path)
If sWrkbkPath <> "" Then
Set UnionWB = Workbooks.Open(sWrkbkPath)
MsgBox UnionWB.Name
End If
End Sub
Function GetFile(Optional startFolder As Variant = -1) As Variant
Dim fle As FileDialog
Dim vItem As Variant
Set fle = Application.FileDialog(msoFileDialogFilePicker)
With fle
.Title = "Select your Union Workbook"
.AllowMultiSelect = False
.Filters.Add "My Union Workbook", "*.xlsx", 1
If startFolder = -1 Then
.InitialFileName = Application.DefaultFilePath
Else
If Right(startFolder, 1) <> "\" Then
.InitialFileName = startFolder & "\"
Else
.InitialFileName = startFolder
End If
End If
If .Show <> -1 Then GoTo NextCode
vItem = .SelectedItems(1)
End With
NextCode:
GetFile = vItem
Set fle = Nothing
End Function
The second method assumes you only have a single xlsx file in the same folder as ThisWorkbook and opens the first file it finds:
Public Sub OpenOnlyXLSXInFolder()
Dim sWrkbkPath As String
Dim UnionWB As Workbook
sWrkbkPath = Dir$(ThisWorkbook.Path & "\*.xlsx")
'Only expecting a single file so no need to loop.
If sWrkbkPath <> "" Then
Set UnionWB = Workbooks.Open(ThisWorkbook.Path & "\" & sWrkbkPath)
MsgBox UnionWB.Name
End If
End Sub