| Namespace | Windows.Devices.Midi2.Transports.Bluetooth |
|---|---|
| Type Name | MidiBluetoothTransportManager |
| Type | WinRT Runtime Class |
| IDL | MidiBluetoothTransportManager.idl |
| Static Property | Description |
|---|---|
IsTransportAvailable |
Returns true if this transport is available in the service. |
TransportId |
Returns the GUID of this transport. |
| Static Method | Description |
|---|---|
GetAvailableDevices() |
Returns every Bluetooth MIDI device this PC has seen advertising, as a collection of MidiBluetoothDeviceInformation, whether or not each is connected. |
GetDevice(bluetoothDeviceId) |
Returns the MidiBluetoothDeviceInformation for one device, or null when no device with that address has been discovered. |
ConnectDeviceAsync(connectConfig) |
Connects to a device and creates a MIDI endpoint for it. Returns a MidiBluetoothDeviceConnectResponse. |
DisconnectDeviceAsync(disconnectConfig) |
Disconnects a device and removes its MIDI endpoint. Returns a MidiBluetoothDeviceDisconnectResponse. |
StartPeripheralAsync(peripheralConfig) |
Publishes this PC so other devices can connect to it. Returns a MidiBluetoothPeripheralResponse. |
StopPeripheralAsync() |
Stops publishing this PC. Returns a MidiBluetoothPeripheralResponse. |
GetPeripheralStatus() |
Returns the current MidiBluetoothPeripheralStatus. |
GetPendingPeripheralClients() |
Returns the remote Centrals which have connected and are waiting for a decision, as MidiBluetoothPeripheralClient entries. |
ApprovePeripheralClientAsync(bluetoothAddress, scope) |
Approves a waiting remote Central for the given MidiBluetoothApprovalScope. Returns a MidiBluetoothPeripheralClientDecisionResponse. |
DenyPeripheralClientAsync(bluetoothAddress, scope) |
Denies a waiting remote Central. |
ForgetPeripheralClientAsync(bluetoothAddress) |
Drops a remembered allow or deny, so the device is asked about again next time. |
GetRadioInformation() |
Returns what this PC’s Bluetooth radio can do, as MidiBluetoothRadioInformation, or null on a service too old to report it. |
GetDefaultOfflineRetentionSeconds() |
Returns the transport-wide value every device set to UseTransportDefault falls back to. Never UseTransportDefault itself. |
One manager covers both Bluetooth Low Energy MIDI 1.0 and 2.0. Which protocol a device speaks is chosen by the transport, which prefers MIDI 2.0 whenever a device offers it.
Bluetooth does not let Windows refuse an incoming connection. A remote Central which connects while the policy is RequireApproval stays connected but has no MIDI endpoint and moves no data until it is decided about, so an application which never calls GetPendingPeripheralClients leaves it stuck there silently.
The address passed to ApprovePeripheralClientAsync and DenyPeripheralClientAsync must be the one reported for the client which is waiting. A decision made against a stale list is rejected with ClientIdentityMismatch rather than applied to whoever connected since.
Connecting and disconnecting are asynchronous because the radio has to find the device, open its GATT service, and subscribe to a characteristic. That takes seconds, and longer for a device which is asleep.
Passing a MidiBluetoothDeviceConnectConfig to ConnectDeviceAsync connects the device now, for this session only. Passing the same object to MidiServiceTransportPluginConfigManager.SaveUpdate writes it to the configuration file so it reconnects after the service restarts.
auto config = MidiBluetoothDeviceConnectConfig(L"48B6201A719D");
auto response = co_await MidiBluetoothTransportManager::ConnectDeviceAsync(config);
if (response.Success())
{
// keep it across service restarts
MidiServiceTransportPluginConfigManager::SaveUpdate(config);
}
The same applies in reverse. Saving a MidiBluetoothDeviceDisconnectConfig stops the device connecting on its own; constructing it with removeFromConfiguration set takes the entry out of the file entirely.
A connection request is remembered rather than performed, so a request for a device which is switched off succeeds and connects later, when the device appears. MidiBluetoothDeviceConnectResponse.IsKnown and MidiBluetoothDeviceInformation.IsPresent are what distinguish “connecting now” from “waiting for it to appear”, which otherwise look identical.
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.
