VB.NET Test for Google Groups question

Test.vb

Option Explicit On
Imports ExcelDna.Integration  ' for ExcelDnaUtil, XlCall, etc 
Imports System.Math
Imports System.Runtime.InteropServices ' for <ComVisible(True)>
Imports ExcelDna.Integration.CustomUI ' needed for IRibbonControl
Imports DNAIRibbonControl = ExcelDna.Integration.CustomUI.IRibbonControl ' needed for IRibbonControl
Imports Microsoft.Office.Interop
Imports Microsoft.Office.Core
Imports Microsoft.Office.Interop.Excel ' Các giao diện như Workbook, Range
Module Globals
    Public ReadOnly Property Application As Application
        Get
            Application = ExcelDnaUtil.Application
        End Get
    End Property
End Module



<ComVisible(True)> Public Class MyRibbon
    Inherits ExcelRibbon
    Public Sub New()

    End Sub

    Public Sub PHANBO(control As DNAIRibbonControl)
        ' This action to show message box the content of name and Fullpath of Selected Excel file
        Dim fD As FileDialog
        Dim fullpath, namefile As String
        Dim wbmain As Workbook
        wbmain = Application.ActiveWorkbook
        fD = Application.FileDialog(Microsoft.Office.Core.MsoFileDialogType.msoFileDialogFilePicker)
        With fD
            .AllowMultiSelect = False
            .Title = "Ch" & ChrW(7885) & "n file k" & ChrW(7871) & "t xu" & ChrW(7845) & "t t" & ChrW(7891) & "n kho t" & ChrW(7915) & " Bravo"
            .Filters.Clear()
            .Filters.Add("Excel Files", "*.xlsx; *.xls")
            .InitialFileName = "%USERPROFILE%\Desktop"
        End With
        If fD.Show() = -1 Then
            fullpath = fD.SelectedItems.Item(1)
            namefile = Dir(fD.SelectedItems.Item(1))
        Else : Exit Sub
        End If
        MsgBox("File name is: " & namefile & "Fullpath is: " & fullpath & vbCrLf & "Show Report from Previous Wb:" & wbmain.Name)
    End Sub
End Class

VbTest2019-AddIn.dna

<?xml version="1.0" encoding="utf-8"?>
<DnaLibrary Name="VbTest2019 Add-In" RuntimeVersion="v4.0" xmlns="http://schemas.excel-dna.net/addin/2018/05/dnalibrary">
  <ExternalLibrary Path="VbTest2019.dll" ExplicitExports="false" LoadFromBytes="true" Pack="true" IncludePdb="false" />
    <CustomUI>
      <customUI xmlns="http://schemas.microsoft.com/office/2006/01/customui">
        <ribbon>
          <tabs>
            <tab idMso="TabHome">
              <group id="customsGroup" label="Ttttt" insertBeforeMso="GroupStyles">
                <button id="customButton" label="Check "
      size="large" onAction="PHANBO" imageMso="UpgradeWorkbook" screentip="Click"/>
              </group>
            </tab>
          </tabs>
        </ribbon>
      </customUI>
    </CustomUI>
</DnaLibrary>