...
Dim conn As New MySqlConnection(ConnectionString)
Dim comm As New MySqlCommand
comm.CommandText = "SELECT MyFile FROM MyTable WHERE MyFileId=" & ID
comm.Connection = conn

conn.Open()
Dim fileContent As String = String.Empty
Using reader As MySqlDataReader = comm.ExecuteReader()
If reader.Read() Then
Dim bytes As Byte() = DirectCast(reader("MyFile"), Byte())
MyFileString = System.Text.Encoding.UTF8.GetString(bytes)
End If
End Using
conn.Close()
...

...
Dim xmlDoc As New XmlDocument()
xmlDoc.Load(MyDownloadedFile)
...

"<?xml version=""1.0"" encoding=""utf-8""?>" & vbCrLf & "<ROOT TYPE=""WPL"" DATE=""00.00.0000"">" & vbCrLf & "...

<?xml version="1.0" encoding="utf-8"?>
<ROOT TYPE="WPL" DATE="00.00.0000">
...