Scoping Issues

1 Nov 2006 5:53 PM

MichaelEvans1000

Please someone tell me what i'm doing wrong here. I trying to access
the "files" variable, however i'm getting an "object not set to a
instance". I want to be able to move to the next record if this
"UnauthorizedAccessException" error occurs.

Dim files As ReadOnlyCollection(Of String)
        Dim obj As New WinControl
        Dim WS As New CollectionWS.CollectionBroker
        Dim ds As New System.Data.DataSet
        Dim dt As New System.Data.DataTable
        Dim dr As System.Data.DataRow
        Dim Name As String
        Dim Drive As DriveInfo
        Dim Dname As String

        WS.Credentials = System.Net.CredentialCache.DefaultCredentials

        ds = WS.GetCollectionTypes
        dt = ds.Tables(0)

        'Get Local drive information

        For Each Drive In System.IO.DriveInfo.GetDrives

            Dname = Drive.Name
            For Each dr In dt.Rows
                Try
                    Name = dr.Item(1)
                    files = My.Computer.FileSystem.GetFiles(Dname,
FileIO.SearchOption.SearchTopLevelOnly, "*." & Name)

                    files.GetEnumerator.MoveNext()
                    obj.GetFileProperties(files, Name)
                Catch ex As IOException
                    Exit For
                Catch ex As UnauthorizedAccessException
'I want to move to the next record and try to access it
                    files.GetEnumerator.MoveNext()

                End Try
            Next
        Next

1 Nov 2006 6:13 PM

Marina Levit [MVP]

What it means, is that the exception was thrown on the GetFiles call while
you were trying to assign a value to 'files'. Because an exception was
thrown, 'files' never got a value. It is still null.

Yet, in your catch, you are trying to use files. Well, you can't, it never
got a value, GetFiles failed and the files were never retrieved.

<MichaelEvans1***@gmail.com> wrote in message
Show quoteHide quote

news:1162403587.385738.299030@e64g2000cwd.googlegroups.com...
> Please someone tell me what i'm doing wrong here. I trying to access
> the "files" variable, however i'm getting an "object not set to a
> instance". I want to be able to move to the next record if this
> "UnauthorizedAccessException" error occurs.
>
> Dim files As ReadOnlyCollection(Of String)
>        Dim obj As New WinControl
>        Dim WS As New CollectionWS.CollectionBroker
>        Dim ds As New System.Data.DataSet
>        Dim dt As New System.Data.DataTable
>        Dim dr As System.Data.DataRow
>        Dim Name As String
>        Dim Drive As DriveInfo
>        Dim Dname As String
>
>        WS.Credentials = System.Net.CredentialCache.DefaultCredentials
>
>        ds = WS.GetCollectionTypes
>        dt = ds.Tables(0)
>
>        'Get Local drive information
>
>        For Each Drive In System.IO.DriveInfo.GetDrives
>
>            Dname = Drive.Name
>            For Each dr In dt.Rows
>                Try
>                    Name = dr.Item(1)
>                    files = My.Computer.FileSystem.GetFiles(Dname,
> FileIO.SearchOption.SearchTopLevelOnly, "*." & Name)
>
>                    files.GetEnumerator.MoveNext()
>                    obj.GetFileProperties(files, Name)
>                Catch ex As IOException
>                    Exit For
>                Catch ex As UnauthorizedAccessException
> 'I want to move to the next record and try to access it
>                    files.GetEnumerator.MoveNext()
>
>                End Try
>            Next
>        Next
>

1 Nov 2006 6:46 PM

Göran_Andersson

The exception is thrown when you try to get the list of files, as you
don't have access to the folder. As you don't get any list of files, you
can not move to the next file.

MichaelEvans1***@gmail.com wrote:
Show quoteHide quote

> Please someone tell me what i'm doing wrong here. I trying to access
> the "files" variable, however i'm getting an "object not set to a
> instance". I want to be able to move to the next record if this
> "UnauthorizedAccessException" error occurs.
>
> Dim files As ReadOnlyCollection(Of String)
>         Dim obj As New WinControl
>         Dim WS As New CollectionWS.CollectionBroker
>         Dim ds As New System.Data.DataSet
>         Dim dt As New System.Data.DataTable
>         Dim dr As System.Data.DataRow
>         Dim Name As String
>         Dim Drive As DriveInfo
>         Dim Dname As String
>
>         WS.Credentials = System.Net.CredentialCache.DefaultCredentials
>
>         ds = WS.GetCollectionTypes
>         dt = ds.Tables(0)
>
>         'Get Local drive information
>
>         For Each Drive In System.IO.DriveInfo.GetDrives
>
>             Dname = Drive.Name
>             For Each dr In dt.Rows
>                 Try
>                     Name = dr.Item(1)
>                     files = My.Computer.FileSystem.GetFiles(Dname,
> FileIO.SearchOption.SearchTopLevelOnly, "*." & Name)
>
>                     files.GetEnumerator.MoveNext()
>                     obj.GetFileProperties(files, Name)
>                 Catch ex As IOException
>                     Exit For
>                 Catch ex As UnauthorizedAccessException
> 'I want to move to the next record and try to access it
>                     files.GetEnumerator.MoveNext()
>
>                 End Try
>             Next
>         Next
>