Imports System.Security.Permissions
 
Public Declare Function FindMimeFromData Lib "urlmon.dll" (ByVal pBC As IntPtr, <MarshalAs(UnmanagedType.LPWStr)> ByVal pwzUrl As String, <MarshalAs(UnmanagedType.LPArray, ArraySubType:=UnmanagedType.I1, SizeParamIndex:=3)> ByVal pBuffer As Byte(), ByVal cbSize As Integer, <MarshalAs(UnmanagedType.LPWStr)> ByVal pwzMimeProposed As String, ByVal dwMimeFlags As Integer, <MarshalAs(UnmanagedType.LPWStr)> ByRef ppwzMimeOut As String, ByVal dwReserved As Integer) As Integer
 
 
Public Shared Function getMimeFromFile(ByVal file As String) As String
 
        Dim mimeout As IntPtr
 
        If Not System.IO.File.Exists(file) Then
            Throw New FileNotFoundException(file + " not found")
        End If
 
        Dim MaxContent As Integer = CInt(New FileInfo(file).Length)
 
        If MaxContent > 4096 Then
            MaxContent = 4096
        End If
 
        Dim fs As New FileStream(file, FileMode.Open)
 
        Dim buf(MaxContent) As Byte
        fs.Read(buf, 0, MaxContent)
        fs.Close()
 
        Dim result As Integer = FindMimeFromData(IntPtr.Zero, file, buf, MaxContent, Nothing, 0, mimeout, 0)
 
        If result <> 0 Then
            'Throw Marshal.GetHRForExceptionresult)
        End If
 
        Dim mime As String = Marshal.PtrToStringUni(mimeout)
 
        Marshal.FreeCoTaskMem(mimeout)
 
        Return mime
 
    End Function