Add String To File MD5 Hash In VB.NET?

I'm trying to calculate the hash of a file with MD5 and then add the filename to the data before i encrypt it with MD5. The filename should be added to the end of the file before encryption

So it looks something like md5(filedatabytes & filename)

Here's my code:

Code:

---

    Public Class FileChecksum
    Private Const BUF_SIZE As Integer = 65536
    ''' <summary>
    ''' Returns the file integrity checksum hash, otherwise an empty string.
    ''' </summary>
    Public Shared Function IntegrityCheck(ByVal filePath As String) As String
        Dim dataBuffer(BUF_SIZE - 1) As Byte
        Dim dataBufferDummy(BUF_SIZE - 1) As Byte
        Dim dataBytesRead As Integer = 0
        Dim hashResult As String = String.Empty
        Dim hashAlg As HashAlgorithm = Nothing
        Dim fs As FileStream = Nothing

        Try
            hashAlg = New MD5CryptoServiceProvider ' or New SHA1CryptoServiceProvider
            fs = New FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.None, BUF_SIZE)
            Do
                dataBytesRead = fs.Read(dataBuffer, 0, BUF_SIZE)
                hashAlg.TransformBlock(dataBuffer, 0, dataBytesRead, dataBufferDummy, 0)
            Loop Until dataBytesRead = 0

            hashAlg.TransformFinalBlock(dataBuffer, 0, 0)

            hashResult = BitConverter.ToString(hashAlg.Hash).Replace("-", "").ToLower
        Catch ex As IOException
            MsgBox(ex.Message, MsgBoxStyle.Critical, "IntegrityCheck")
        Catch ex As UnauthorizedAccessException
            MsgBox(ex.Message, MsgBoxStyle.Critical, "IntegrityCheck")
        Finally
            If Not fs Is Nothing Then
                fs.Close()
                fs.Dispose()
                fs = Nothing
            End If
            If Not hashAlg Is Nothing Then
                hashAlg.Clear() 'Dispose()
                hashAlg = Nothing
            End If
        End Try
        Return hashResult
    End Function

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Label4.Text = IntegrityCheck("D:\My Documents\My Games\FarmingSimulator2015\mods\weight6000.zip")
    End Sub
End Class

---

But how do i add the filename before encrypting?

In this case it should add weight6000 before calculating the MD5.

Here is what i try to achieve written in PHP:

Code:

---

function getGiantsModMD5Hash($modFile)
{
  $info = pathinfo($modFile);
  // Add mod zip data
  $fileContent = file_get_contents($modFile);
  // Add basefile name string without extension
  $fileContent .= basename($modFile, '.' . $info['extension']);
  return md5($fileContent);
}

---

I haven't tested this and haven't done much hashing myself, but it seems to me that you could use an appropriate Encoding object and call GetBytes to convert the file name to a Byte array and then pass that when you call TransformFinalBlock.