Imports System
Imports System.Runtime
Imports System.Runtime.InteropServices
 
Public Class Form1
 
    Private Declare Function midiOutGetNumDevs Lib "winmm.dll" () As Short
    Private Declare Function midiOutGetDevCaps Lib "winmm.dll" Alias _
      "midiOutGetDevCapsA" (ByVal uDeviceID As Integer, ByRef lpCaps As _
      MIDIOUTCAPS, ByVal uSize As Integer) As Integer
 
    Private Const MAXPNAMELEN As Integer = 32
 
    'Konstanten die den Inhalt von MIDIOUTCAPS.wTechnologie beschreiben
    Private Const MOD_MIDIPORT As Short = 1
    Private Const MOD_SYNTH As Short = 2
    Private Const MOD_SQSYNTH As Short = 3
    Private Const MOD_FMSYNTH As Short = 4
    Private Const MOD_MAPPER As Short = 5
    Private Const MOD_WAVETABLE As Short = 6
    Private Const MOD_SWSYNTH As Short = 7
 
    'String die den Inhalt von MIDIOUTCAPS.wTechnologie beschreiben
    Private Technologie() As String = {"Unkonwn", "MIDI hardware port", _
      "Synthesizer", "Square wave synthesizer", "FM synthesizer", "Microsoft" & _
      "MIDI mapper", "Hardware wavetable synthesizer", "Software synthesizer", _
      "Unknown"}
 
    <StructLayout(LayoutKind.Sequential)> Private Structure MIDIOUTCAPS
        Public Const MAXPNAMELEN = 32
        Public wMid As Short
        Public wPid As Short
        Public vDriverVersion As Int32
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAXPNAMELEN)> Public _
          szPname As String
        Public wTechnology As Short
        Public wVoices As Short
        Public wNotes As Short
        Public wChannelMask As Short
        Public dwSupport As Int32
    End Structure
 
    Private Sub Form1_Shown(ByVal sender As Object, ByVal e As _
      System.EventArgs) Handles Me.Shown
        Dim count As Short = midiOutGetNumDevs
        Dim midicaps As New MIDIOUTCAPS
        For i As Integer = 0 To count - 1
            'holt alle midi-device eingenschaften
            midiOutGetDevCaps(i, midicaps, CInt(Marshal.SizeOf(midicaps)))
            'darstellen der informationen
            With midicaps
                MessageBox.Show("Manufacturer identifier:     " & _
                  .wMid.ToString & vbCrLf & _
                                "Product identifier:     " & .wPid.ToString & _
                                vbCrLf & _
                                "Version number of the device driver:     " & _
                                .vDriverVersion.ToString & vbCrLf & _
                                "Product name:     " & .szPname & vbCrLf & _
                                "Type of the MIDI output device:     " & _
                                Technologie(.wTechnology) & vbCrLf & _
                                "Number of voices supported:     " & _
                                .wVoices.ToString & vbCrLf & _
                                "Maximum number of simultaneous notes:      " & _
                                .wNotes.ToString & vbCrLf & _
                                "Channels that an internal synthesizer:     " & _
                                .wChannelMask.ToString & vbCrLf & _
                                "Optional functionality supported by the" & _
                                "device:      " & .dwSupport.ToString)
            End With
        Next
    End Sub
End Class