public bool IsFile { get; }

Public ReadOnly Property IsFile As Boolean
	Get

// To use the code below, import MailBee namespaces at the top of your code.
using MailBee;
using MailBee.Mime;

// The actual code (put it into a method of your class).
MailMessage msg = new MailMessage();
msg.LoadMessage(@"C:\Docs\TestMail.eml");
foreach (MimePart part in msg.MimePartTree.GetAllParts())
{
    if (part.IsFile)
    {
        Console.WriteLine("MIME part " + part.Filename + " is file.");
    }
}

' To use the code below, import MailBee namespaces at the top of your code.
Imports MailBee
Imports MailBee.Mime

' The actual code (put it into a method of your class).
Dim msg As New MailMessage
msg.LoadMessage("C:\Docs\TestMail.eml")
For Each part As MimePart In msg.MimePartTree.GetAllParts()
    If part.IsFile Then
        Console.WriteLine("MIME part " & part.Filename & " is file.")
    End If
Next