Source-Generated COM Sample
This tutorial demonstrates how to use COM source generators in .NET 8+ to create a COM server and client for in-process COM.
This example defines an interface ICalculator that provides Add and Subtract methods. The server provides an implementation of ICalculator for the client to use after the server has been registered. The client project creates an instance of the object using the CoCreateInstance Win32 method, and calls methods on the object.
This sample supports NativeAOT and standard CoreCLR deployments. The native methods that the Windows COM system requires are exported automatically with the [UnmanagedCallersOnly] attribute when publishing with NativeAOT. For CoreCLR, the DNNE package is used to provide the exported functions.
Prerequisites
- .NET 8+ SDK
- Windows 10+ OS
Build and Run
NativeAOT
Build the Native AOT binaries by running dotnet publish -r <RID> where <RID> is the RuntimeIdentifier for your OS, for example win-x64. The projects will copy the binaries to the OutputFiles\ directory. After publishing, use regsvr32.exe to register Server.dll with COM by running run regsvr32.exe .\OutputFiles\Server\Server.dll. Then, run the client application .\OutputFiles\Client\Client.exe and observe the output as it activates and uses a COM instance from Server.dll. When you are finished, unregister the server by running regsvr32.exe /u .\OutputFiles\Server\Server.dll.
CoreCLR
Build the projects by running dotnet publish. The projects will copy the binaries to the OutputFiles\ directory. After publishing, use regsvr32.exe to register the native binary produced by DNNE, ServerNE.dll, by running regsvr32.exe .\OutputFiles\Server\ServerNE.dll. ServerNE.dll will start the .NET runtime and call the exported methods in the managed Server.dll which register the server with COM. Then, run the client application .\OutputFiles\Client\Client.exe and observe the output as it activates and uses a COM instance from ServerNE.dll. When you are finished, unregister the server by running regsvr32.exe /u .\OutputFiles\Server\ServerNE.dll.