How to fix a CA2000 IDisposable C# compiler warning, when using a global cache

Question

CA2000 is a warning regarding the IDisposable interface:

CA2000 : Microsoft.Reliability : In method \'ImportProcessor.GetContext(string)\', call Sys

Answer 1

Michael's solution does not seem to work when converted to VB.Net. The following two functions were tested under VS 2017:

    Public Function OpenStream(ByVal filePathName As String) As System.IO.FileStream
        Dim fileStream As System.IO.FileStream = Nothing
        Dim tempFileStream As System.IO.FileStream = Nothing
        If Not String.IsNullOrWhiteSpace(filePathName) Then
            Try
                tempFileStream = New System.IO.FileStream(filePathName, System.IO.FileMode.Open, System.IO.FileAccess.Read)
                fileStream = tempFileStream
            Catch
                tempFileStream?.Dispose()
                Throw
            End Try
        End If
        Return fileStream
    End Function

    Public Function OpenReader(ByVal filePathName As String) As System.IO.BinaryReader
        If String.IsNullOrWhiteSpace(filePathName) Then Throw New ArgumentNullException(NameOf(filePathName))
        If Not System.IO.File.Exists(filePathName) Then Throw New System.IO.FileNotFoundException("Failed opening a binary reader -- file not found.", filePathName)
        Dim tempReader As System.IO.BinaryReader = Nothing
        Dim reader As System.IO.BinaryReader = Nothing
        Dim stream As IO.FileStream = Nothing
        Try
            stream = Methods.OpenStream(filePathName)
            tempReader = New System.IO.BinaryReader(stream)
            reader = tempReader
        Catch
            stream?.Dispose()
            tempReader?.Dispose()
            Throw
        End Try
        Return reader
    End Function