Vb.net. Denied access to folder. Problem solved

Since the proceedings is complex we'll use an example. In this example i am using a listview and textbox control for text search. This code uses recursive functions.
First of all we'll insert in colde a class. The class is:

Friend Class NativeMethods

        
        Private Shared Function SHGetFileInfo(ByVal pszPath As String,
        ByVal dwFileAttributes As UInteger, ByRef psfi As SHFILEINFO,
        ByVal cbFileInfo As Integer, ByVal uFlags As UInteger) As IntPtr
        End Function

        
        Private Shared Function DestroyIcon(ByVal hIcon As IntPtr) As IntPtr
        End Function

        
        Public Structure SHFILEINFO
            Implements IDisposable

            Public hIcon As IntPtr
            Public iIcon As Integer
            Public dwAttributes As UInteger
            
            Public szDisplayName As String
            
            Public szTypeName As String

            Public Sub Dispose() Implements System.IDisposable.Dispose
                DestroyIcon(Me.hIcon)
            End Sub
        End Structure

        Private Const SHGFI_ICON As UInt32 = &H100
        Private Const SHGFI_DISPLAYNAME As UInt32 = &H200
        Private Const SHGFI_TYPENAME As UInt32 = &H400
        Private Const SHGFI_LARGEICON As UInt32 = 0
        Private Const SHGFI_SMALLICON As UInt32 = 1

        Public Shared Function GetInfoFromShell(ByVal FileName As String) As SHFILEINFO
            Dim shfi As SHFILEINFO = New SHFILEINFO
            shfi.hIcon = IntPtr.Zero
            SHGetFileInfo(FileName, 0, shfi, Marshal.SizeOf(shfi), SHGFI_TYPENAME Or SHGFI_ICON Or SHGFI_SMALLICON)
            Return shfi
        End Function

    End Class

For all extensions except pdf:

 
Public Sub GetFiles(ByVal strFileFilter As String, ByVal strDirectory As String, ByVal intDepthLimit As Integer, ByVal intCurrentDepth As Integer)
            Try
                Dim folderInfo As New DirectoryInfo(strDirectory)

                ' Is the current depth on this recursion less than our limit?
                ' If so, find any directories and get into them by calling GetFiles recursively (incrementing depth count)
                If intCurrentDepth < intDepthLimit Then
                    Dim directories() As DirectoryInfo
                    directories = folderInfo.GetDirectories()

                    For Each fDirectory In directories
                        ' Recursively call ourselves incrementing the depth using the given folder path.
                        GetFiles(strFileFilter, fDirectory.FullName, intDepthLimit, intCurrentDepth + 1)
                    Next
                End If

                ' After we can't go further down, add any files which match our filter to listbox (in this case lstFiles)
                Dim files() As FileInfo
                files = folderInfo.GetFiles(strFileFilter)
                Dim sh As New NativeMethods.SHFILEINFO

                Dim exeIcon As System.Drawing.Icon
                listView1.BeginUpdate()
                For Each fFile In files
                    Dim reader = My.Computer.FileSystem.ReadAllText(fFile.FullName,
   System.Text.Encoding.ASCII)
                    If reader.Contains(TextBox1.Text) Then
                        If Not fFile.FullName.EndsWith("dll") And Not fFile.FullName.EndsWith("exe") _
                            And Not fFile.FullName.EndsWith("res") And Not fFile.FullName.EndsWith("tx") _
And Not fFile.FullName.EndsWith("pak") And Not fFile.FullName.EndsWith("xls") And Not fFile.FullName.EndsWith("pdf") _
And Not fFile.FullName.EndsWith("pcv") Then
                            Application.DoEvents()
                            listView1.SmallImageList = ImageList1
                            listView1.LargeImageList = ImageList1
                            ImageList1.ColorDepth = ColorDepth.Depth32Bit
                            sh = NativeMethods.GetInfoFromShell(fFile.FullName)
                            exeIcon = CType(System.Drawing.Icon.FromHandle(sh.hIcon).Clone, Icon)
                            ImageList1.ColorDepth = ColorDepth.Depth32Bit
                            sh = NativeMethods.GetInfoFromShell(fFile.FullName)


                            exeIcon = CType(System.Drawing.Icon.FromHandle(sh.hIcon).Clone, Icon)

                            If (ImageList1.Images.ContainsKey(fFile.FullName)) Then
                                listView1.Items.Add(fFile.FullName, fFile.FullName)
                            ElseIf (Not exeIcon Is Nothing) Then
                                ImageList1.Images.Add(fFile.FullName, exeIcon)
                                listView1.Items.Add(fFile.FullName, fFile.FullName)
                            Else
                                listView1.Items.Add(fFile.FullName)
                            End If


                        End If
                    End If
                Next
                listView1.EndUpdate()

                remov()
            Catch ex As Exception

            End Try
        End Sub
        
        

'remov' routine serves to remove duplicate files from listview Here is remov routine:

 Private Sub remov()
            Try
                Dim i, j As Integer
                With Me.listView1
                    Do Until i > .Items.Count - 2
                        Dim text As String = .Items(i).Text
                        j = i + 1
                        Do Until j > .Items.Count - 1
                            If .Items(j).Text = text Then
                                .Items.RemoveAt(j)
                            Else
                                j += 1
                            End If
                        Loop
                        i += 1
                    Loop
                End With
            Catch
            End Try
        End Sub
                  

For pdf files the function is:

Public Sub GetFiles1(ByVal strFileFilter As String, ByVal strDirectory As String, ByVal intDepthLimit As Integer, ByVal intCurrentDepth As Integer)
            Try
                Dim folderInfo As New DirectoryInfo(strDirectory)

                ' Is the current depth on this recursion less than our limit?
                ' If so, find any directories and get into them by calling GetFiles recursively (incrementing depth count)
                If intCurrentDepth < intDepthLimit Then
                    Dim directories() As DirectoryInfo
                    directories = folderInfo.GetDirectories()

                    For Each fDirectory In directories
                        ' Recursively call ourselves incrementing the depth using the given folder path.
                        GetFiles1(strFileFilter, fDirectory.FullName, intDepthLimit, intCurrentDepth + 1)
                    Next
                End If

                ' After we can't go further down, add any files which match our filter to listbox (in this case lstFiles)

                Dim files() As FileInfo
                files = folderInfo.GetFiles(strFileFilter)


                For Each namo In files
                    counter = counter + 1

                    Dim text As StringBuilder = New StringBuilder

                    Dim pdfReader As PdfReader = New PdfReader(namo.FullName)
                    Dim page As Integer = 1
                    Do While (page <= pdfReader.NumberOfPages)
                        Dim strategy As ITextExtractionStrategy = New SimpleTextExtractionStrategy
                        Dim currentText As String = PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy)
                        currentText = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)))
                        text.Append(currentText)
                        page = (page + 1)
                        If currentText.Contains(TextBox1.Text) Then

                            ImageList1.ColorDepth = ColorDepth.Depth32Bit
                            Dim sh As New NativeMethods.SHFILEINFO

                            sh = NativeMethods.GetInfoFromShell(namo.FullName)
                            Dim theIcon As Icon
                            If sh.hIcon <> IntPtr.Zero Then



                                listView1.LargeImageList = ImageList1
                                listView1.SmallImageList = ImageList1
                                listView1.View = View.SmallIcon
                                theIcon = DirectCast(System.Drawing.Icon.FromHandle(sh.hIcon).Clone, System.Drawing.Icon)


                                ImageList1.Images.Add(namo.FullName, theIcon.Clone)
                                listView1.Items.Add(namo.FullName, namo.FullName)
                            End If
                        End If
                    Loop

                    pdfReader.Close()


                Next
                remov()
                listView1.View = View.Details
                listView1.HeaderStyle = ColumnHeaderStyle.None
                listView1.FullRowSelect = True
                listView1.Columns.Add("", -2)

            Catch ex As Exception

            Finally

            End Try
        End Sub
        
       

To launch Getfiles and Getfiles1, examples: GetFiles("*.ico", "C:\\myicons", 1, 0); GetFiles1("*.pdf", "C:\\Docu", 1, 0)
References: https://www.coderslexicon.com/playing-with-recursive-directory-diving-in-vb-net

Greetings to all.