Locate all Monitors

private
    { Private-Deklarationen }
    Procedure FillMonitorList;

//

Procedure TForm1.FillMonitorList;
Var
	  Cntr        : Cardinal;
	  Info        : TDisplayDevice;
	  AdapterName : PChar;
	  OldPos      : Integer;
Const
	  DISPLAY_DEVICE_ATTACHED_TO_DESKTOP = $00000001;
	  DISPLAY_DEVICE_MULTI_DRIVER        = $00000002;
	  DISPLAY_DEVICE_PRIMARY_DEVICE      = $00000004;
	  DISPLAY_DEVICE_MIRRORING_DRIVER    = $00000008;
	  DISPLAY_DEVICE_VGA                 = $00000010;
Begin
	  ListBox1.Items.Add('------------------ Displays ----------------');

	  Cntr := 0;
	  Info.cb := SizeOf(Info);
	  While EnumDisplayDevices(Nil, Cntr, Info, 0) Do
	  Begin
	    ListBox1.Items.Add('* Device '+IntToStr(Cntr)+':');
	    ListBox1.Items.Add('    DeviceName  : '+Info.DeviceName);
	    ListBox1.Items.Add('    DeviceString: '+Info.DeviceString);

	    OldPos := ListBox1.Items.Add('    StateFlags:   ');

	    If ( Info.StateFlags And DISPLAY_DEVICE_ATTACHED_TO_DESKTOP ) = DISPLAY_DEVICE_ATTACHED_TO_DESKTOP Then
	      ListBox1.Items.Add('      + Display Device Attached To Desktop')
	    Else
	      ListBox1.Items.Add('      - Display Device Attached To Desktop');

	    If ( Info.StateFlags And DISPLAY_DEVICE_MULTI_DRIVER ) = DISPLAY_DEVICE_MULTI_DRIVER Then
	      ListBox1.Items.Add('      + Display Device Multi Driver')
	    Else
	      ListBox1.Items.Add('      - Display Device Multi Driver');

	    If ( Info.StateFlags And DISPLAY_DEVICE_PRIMARY_DEVICE ) = DISPLAY_DEVICE_PRIMARY_DEVICE Then
	      ListBox1.Items.Add('      + Display Device Primary Device')
	    Else
	      ListBox1.Items.Add('      - Display Device Primary Device');

	    If ( Info.StateFlags And DISPLAY_DEVICE_MIRRORING_DRIVER ) = DISPLAY_DEVICE_MIRRORING_DRIVER Then
	      ListBox1.Items.Add('      + Display Device Mirroring Driver')
	    Else
	      ListBox1.Items.Add('      - Display Device Mirroring Driver');

	    If ( Info.StateFlags And DISPLAY_DEVICE_VGA ) = DISPLAY_DEVICE_VGA Then
	      ListBox1.Items.Add('      + Display Device VGA')
	    Else
	      ListBox1.Items.Add('      - Display Device VGA');


	    AdapterName := StrAlloc(SizeOf(Info.DeviceName));
	    StrCopy(AdapterName, Info.DeviceName);
	    EnumDisplayDevices(AdapterName, 0, Info, 0);
	    ListBox1.Items.Insert(OldPos, '    Monitorname : ' + Info.DeviceString);
	    StrDispose(AdapterName);

	    Inc(Cntr);
	  End;
End;

Beispiel :

procedure TForm1.Button1Click(Sender: TObject);
begin
   FillMonitorList
end;