I'm trying to fix two warnings. The first warning is an implicit conversion from long to string on the oInfo.Length. The second is Implicit conversion from string to double on 'strSize'. This is an old .NET 1 project I'm try to convert to 4.0. How do I fix these warnings while keeping the logic? 

```
 Dim oInfo As New System.IO.FileInfo(Server.MapPath(strVirtualPath))
    Dim strSize As String = ""
    Try
        If oInfo.Exists Then
            strSize = **oInfo.Length**
            If **strSize** < 1048576 Then
                strSize = System.Math.Round(Convert.ToInt64(strSize) / 1024, 2) & " kb"
            Else
                strSize = System.Math.Round(Convert.ToInt64(strSize) / 1048576, 2) & " mb"
            End If
        End If
    Catch ex As Exception

```