Getting Cannot access a closed file error - vb.net

Question

I use the following code to iterate a collection of files that I need to copy from one folder to another. It works fine when the source file exist, but when it does not exist I get
System.ObjectDisposedException: Cannot access a closed file. at System.IO.__Error.FileNotOpen() at System.IO.FileStream.get_Position()
What am I missing here?
For Each itm In listOfFiles
Try
If File.Exists(itm.SourcePath + itm.FileName) Then
Dim cf As New FileStream(itm.SourcePath + itm.FileName, FileMode.Open)
Dim ct As New FileStream(itm.DestinationPath + itm.FileName, FileMode.Create)
Dim len As Long = cf.Length - 1
Dim buffer(1024) As Byte
Dim byteCFead As Integer
While cf.Position < len
byteCFead = (cf.Read(buffer, 0, 1024))
ct.Write(buffer, 0, byteCFead)
fileCopyProgressBar.BeginInvoke(New Action(Sub() fileCopyProgressBar.Value = CInt(cf.Position / len * 100)))
End While
ct.Flush()
ct.Close()
cf.Close()
itm.FileExsits = True
Else
itm.FileExsits = False
End If
Catch ex As Exception
log.Error(ex.Message & " (unc)")
End Try
Next

Answer 1

Try calculating value before putting it in the action. You should also dispose of the streams when done with them
For Each itm In listOfFiles
Try
If File.Exists(itm.SourcePath + itm.FileName) Then
Using cf As New FileStream(itm.SourcePath + itm.FileName, FileMode.Open)
Using ct As New FileStream(itm.DestinationPath + itm.FileName, FileMode.Create)
Dim len As Long = cf.Length - 1
Dim buffer(1024) As Byte
Dim byteCFead As Integer
Dim percentage As Integer
While cf.Position < len
byteCFead =(cf.Read(buffer, 0, 1024))
ct.Write(buffer, 0, byteCFead)
percentage = CInt(cf.Position / len * 100)
fileCopyProgressBar.BeginInvoke(New Action(Sub() fileCopyProgressBar.Value = percentage))
End While
ct.Flush()
ct.Close()
cf.Close()
End Using
End Using
itm.FileExsits = True
Else
itm.FileExsits = False
End If
Catch ex As Exception
log.Error(ex.Message & " (unc)")
End Try
Next