libCEC — .NET API (LibCecSharp)

LibCecSharp (namespace CecSharp) is the managed binding for libCEC: a pure C# assembly that binds the native library through its C API (P/Invoke over cecc.h), targeting net8.0. Unlike the old C++/CLI wrappers it runs anywhere the native library does — Windows, Linux, macOS and Raspberry Pi.

It lets .NET applications control CEC-capable HDMI devices — power a TV on or to standby, become the active source, send remote keys, read device state — and receive bus events. Every binding wraps the same engine, so the concepts match the C/C++ reference, which documents them in the most depth.

Requirements

• A Pulse-Eight USB-CEC adapter (or a supported SoC-native CEC backend).
• The native libCEC library available at runtime (cec.dll on Windows, libcec.so on Linux, libcec.dylib on macOS).
• The .NET 8 runtime (the Windows installer prompts for the .NET 8 Desktop Runtime when the managed component is selected).

Installing

Debian / Ubuntu

sudo apt-get install libcec-dotnet

This installs the LibCecSharp assembly and its NuGet package alongside the native library.

Windows

The USB-CEC Adapter software installer ships LibCecSharp.dll and the native cec.dll together (select the managed component). To build both from source, run python windows\create-installer.py, which drives cmake with -DENABLE_DOTNET_LIB=1.

Build from source (any platform with the .NET SDK)

The managed binding is a cmake option, off by default:

mkdir build && cd build
cmake .. -DENABLE_DOTNET_LIB=1
make -j4

Add -DENABLE_DOTNET_APPS=1 to also build the Windows-only cec-tray and the cross-platform CecSharpTester sample. Reference the resulting LibCecSharp.dll (or its NuGet package) from your project, and make sure the native library is on the loader path at runtime.

Using the API

Derive from CecCallbackMethods to receive events, describe yourself in a LibCECConfiguration, then construct LibCecSharp and open a connection.

using CecSharp;

// 1. handle events by overriding the callback methods
class CecClient : CecCallbackMethods
{
    public override int ReceiveLogMessage(CecLogMessage message)
    {
        Console.WriteLine($"log: {message.Message}");
        return 1;
    }

    public override int ReceiveKeypress(CecKeypress key)
    {
        Console.WriteLine($"key: {key.Keycode}");
        return 1;
    }
}

var client = new CecClient();

// 2. describe this client
var config = new LibCECConfiguration();
config.DeviceName = "CecSharp";
config.DeviceTypes.Types[0] = CecDeviceType.RecordingDevice;
config.ClientVersion = LibCECConfiguration.CurrentVersion;
config.Callbacks = client;

// 3. create the instance and open the first adapter found
using var lib = new LibCecSharp(client, config);
CecAdapter[] adapters = lib.FindAdapters(string.Empty);
if (adapters.Length > 0 && lib.Open(adapters[0].ComPort, 10000))
{
    // 4. control the bus
    lib.PowerOnDevices(CecLogicalAddress.Tv);
    foreach (var address in lib.GetActiveDevices().Addresses)
        if (address != CecLogicalAddress.Unknown)
            Console.WriteLine(lib.GetDeviceOSDName(address));

    // 5. clean up
    lib.Close();
}

FindAdapters(string.Empty) enumerates connected adapters; Open connects to one. The callback methods are invoked from libCEC's worker thread, so keep them short. Dispose the LibCecSharp instance (the using above) to close the connection and release the native resources.

See the CecSharpTester console sample and the cec-tray WinForms app in the cec-dotnet repository for complete, runnable programs.

API reference

Browse the full type reference under Api in the navigation, starting with LibCecSharp.