Permission denied when trying to create file on users desktop

Question

I have a small VB app that needs to create a log file, and Ideally I'd like that on the users desktop as it's easy to see.

However, when I try to create the file (a *.txt file), I get the following error -

A first chance exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll

Now, it seems pretty obvious that it's a permissions issue, but I don't know how to work around it, so I wonder if someone can help me out? Thanks.

Full code for creating the file (taken from MSDN, and modifided very slightly) -

Imports System
Imports System.IO
Imports System.Text

Module write_text

    Public Class Log_File

        '*'
        ' Createa a log file on the users desktop and adds the 'output' text to it
        '
        ' @param required string output The text to output to the log
        '*'
        Public Shared Sub write_to_file(ByVal output As String)

            Dim path As String      ' The path to where the file to create and write should be saved
            Dim file_name As String ' The name of the log file that is to be created

            Debug.Print(vbCrLf & "    write_to_file(){" & vbCrLf)

            ' Set the error handler
            On Error GoTo ExitError

            path = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory)
            file_name = "MusicRenaming - " & Date.Today & ".txt"
            Debug.Print("        Log file: " & path & "\" & file_name)

            ' Check if the file exists
            If File.Exists(path) = False Then

                ' Create a file to write too. 
                Dim sw As StreamWriter = File.CreateText(path)
                sw.WriteLine("Hello")
                sw.WriteLine("And")
                sw.WriteLine("Welcome")
                sw.Flush()
                sw.Close()
                Debug.Print("        File had to be created")

            End If

            ' Open the file to write too
            Dim sr As StreamReader = File.OpenText(path)
            Do While sr.Peek() >= 0
                Console.WriteLine(sr.ReadLine())
                Debug.Print("        Output to file complete")
            Loop

            ' Close the file
            sr.Close()

            Debug.Print(vbCrLf & "    }")

ExitError:
            If Err.Number <> 0 Then functions.error_handler()

        End Sub

    End Class

End Module

Please none - I realise that the function isn't particularly operational right now, I'm just trying to get the file created first, then I'll work on that.

Answer 1

Thanks to an answer by @RubensFarias posted in this thread I was able to fix this problem.

I have also incorporated the try...catch method as suggested by @minitech in the comments to my origianl question, so hopefully he is satisfied that I addressed his concerns :)

Imports System.IO

Module write_text

    Public Class Log_File

        '*'
        ' Createa a log file on the users desktop and adds the 'output' text to it
        '
        ' @param required string output The text to output to the log
        '*'
        Public Shared Sub write_to_file(ByVal output As String)

            Dim file_name As String     ' The name of the log file that is to be created
            Dim file_path As String     ' The full path to where the file to create and write should be saved
            Dim file_exists As Boolean  ' Whether or not the file already exists

            Try

                file_name = "MusicRenaming - " & DateTime.Today.ToString("dd-mm-yyyy") & ".txt"
                file_path = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) & "\" & file_name
                file_exists = File.Exists(file_path)

                Using sw As New StreamWriter(File.Open(file_path, FileMode.OpenOrCreate))
                    sw.WriteLine(output)
                End Using

            Catch oError As Exception
                functions.error_handler(oError)
            End Try

        End Sub

    End Class

End Module