Global variable not seen by user form sub - vba

Question

I have set a global dictionary object to keep track of file paths (keys being the "project name" which is the first word of the filename). The way this program works is a form opens in which the user can then open a file dialog to add files to a listbox. When this is done it should add the name and path to the dictionary.
Primary code:
Public project_dict As Scripting.Dictionary
Public Sub excelToPPT()
Set project_dict = New Scripting.Dictionary
...
Dim u As UserForm1
Set u = New UserForm1
u.Show
...
End Sub
UserForm code:
Private Sub cmdAddProject_Click()
Dim project_fd As FileDialog
Set project_fd = Application.FileDialog(msoFileDialogFilePicker)
Dim it As Variant
Dim path_split() As String
Dim f_split() As String
Dim f As String
With project_fd
.AllowMultiSelect = True
.Title = "Select project excel file(s)"
.Filters.Clear
If .Show = -1 Then
For Each it In .SelectedItems
path_split = Split(it, "\")
f_split = Split(path_split(UBound(path_split)))
f = f_split(0)
' WHERE ERROR OCCURS
project_dict.Add f, it
Me.ListBox1.AddItem f
Next it
End If
End With
End Sub
When this is run the error is saying
project_dict.Add f, it
is no good because project_dict is not an object which I assume in this case is a scoping issue. Any ideas?

Answer 1

The issue was solved by placing the below properties in the UserForm code and passing the dictionary in to the form instead of using a global variable.
Dim project_dict As Scripting.Dictionary
Public Property Get ProjectDictionary() As Scripting.Dictionary
Set ProjectDictionary = project_dict
End Property
Public Property Let ProjectDictionary(ByVal pd As Scripting.Dictionary)
Set project_dict = pd
End Property