| Namespace | Windows.Devices.Midi2.Enumeration |
|---|---|
| Type Name | MidiEndpointDeviceHelper |
| Type | WinRT Runtime Class |
| IDL | MidiEndpointDeviceHelper.idl |
There are parts of the Endpoint Device Id which, for a Windows MIDI Service endpoint, are exactly the same. In cases where you may need to display an id in a list or other constrained space, it can be helpful to have a short form of the id. This class is used to convert between the full (long) form and the short form.
For example:
\\?\swd#midisrv#midiu_ksa_9447707571394916916#{e7cce071-3c03-423f-88d3-f1045d02552b}ksa_9447707571394916916Another example:
\\?\swd#midisrv#midiu_loop_b_default_loopback_b#{e7cce071-3c03-423f-88d3-f1045d02552b}loop_b_default_loopback_bYou can see that in both cases, the common information from the beginning, and the interface Id from the end, are both stripped out.
Note: Functions in Windows MIDI Services outside of this class always require the full id. When using shortened ids in the app, always use
GetFullIdFromShortId(shortEndpointDeviceId)before passing the id to a function
This class works on Windows MIDI Services UMP endpoints only. It does not work on WinRT or WinMM MIDI 1.0 port Ids.
| Static Method | Description |
|---|---|
GetShortIdFromFullId(fullEndpointDeviceId) |
Returns the short form of the Endpoint Device Id |
GetFullIdFromShortId(shortEndpointDeviceId) |
Given a short id, returns the full id. No validation is performed to ensure the id is a valid UMP Endpoint |
IsPossibleWindowsMidiServicesEndpointDeviceId(fullEndpointDeviceId) |
Returns true if the endpoint device id appears to be a Windows MIDI Services UMP Endpoint Device Id. No actual lookup is performed. |
IsPossibleWindowsMidiServicesLegacyApiPortDeviceId(legacyPortDeviceId) |
Returns true if the id appears to be a WinRT or WinMM MIDI 1.0 port device id created by Windows MIDI Services. No actual lookup is performed. |
NormalizeFullId(fullEndpointDeviceId) |
Returns the id in normalized form: trimmed and lowercase. |
EnsureCompliantUmpEndpointName(endpointName) |
Returns the supplied name shortened, if necessary, to fit the UMP Endpoint Name limit in the MIDI 2.0 specification. |
EnsureCompliantProductInstanceId(productInstanceId) |
Returns the supplied Product Instance Id with characters which are not valid in a device identifier removed, shortened if necessary to the specification limit. |
The MIDI 2.0 specification states its UMP Endpoint Name and Product Instance Id limits as UTF-8 byte counts, not character counts. A name which looks comfortably short can still exceed the limit once encoded: accented Latin characters take two bytes each, CJK characters three, and emoji four. A 40-character name using CJK characters is 120 bytes, well over the 98 byte endpoint name limit.
EnsureCompliantUmpEndpointName measures in bytes and never cuts a character in half, so the result is always valid text rather than a truncated multi-byte sequence.
Use these when you accept a name or id from a user and want to know what the service will actually store, before you submit it.
Windows MIDI Services is an open source project with all source available on GitHub. We have a great community on Discord as well. Between GitHub and Discord, you should find the information you are looking for.
