I have a weird behavior with the use of Imports System.IO.

I have the following code in File.vb:

Imports System.IO
Imports System.Text

Public Class FileFunction

    ' Create a directory
    ' expC1 Directory
    Public Shared Function MD(ByVal tcDirectory As String)
        Directory.CreateDirectory(tcDirectory)
    End Function

End Class

The Directory line in the MD() function is with error. Basically, the processor can't find the Directory reference. However, the proper imports has been done at the top. If I put the full reference such as:

        System.IO.Directory.CreateDirectory(tcDirectory)

It will work.

Anyone can explain that to me?