Add modern COM interop support by mamoreau-devolutions · Pull Request #173 · Devolutions/MsRdpEx

Marc-André Moreau (mamoreau-devolutions) · 2026-07-22T18:34:41Z

Summary

Adds source-generated COM interop alongside the preserved legacy default package surface.

Keeps legacy Interop.MSTSCLib and AxInterop.MSTSCLib available by default for net48 and net8.0-windows consumers.
Adds opt-in Generated COM interop with NativeAOT support, proxy helpers, typed factories, and connection-point events.
Adds an independent generated WinForms host via MsRdpExGeneratedWinForms=true.
Validates package capabilities and native RID payload architecture during packaging.

Fixes #97.

Credit

Many thanks to Tobias Käs (@weltkante) for the original experimental srcgen / srcgen2 implementation that this work builds upon.

Marc-André Moreau (mamoreau-devolutions) · 2026-07-22T19:00:48Z

Copilot review

Copilot · 2026-07-22T19:08:26Z

Copilot review

Addressed one high-confidence issue from review and pushed a fix in ccdff6a (throw InvalidOperationException in CreateInstanceCore instead of returning it).

Copilot

Pull request overview

Adds opt-in source-generated COM interop and NativeAOT support while retaining the legacy package surface.

Changes:

Adds generated COM interfaces, proxies, events, factories, and WinForms hosts.
Adds package mode selection and architecture/capability validation.
Migrates the sample application and adds compatibility/package tests.

Reviewed changes

Copilot reviewed 62 out of 70 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
`README.md`	Documents interop modes and APIs.
`dotnet/MsRdpEx_Test/Variant.cs`	Adds VARIANT layout tests.
`dotnet/MsRdpEx_Test/Utilities.cs`	Adds reflection test helpers.
`dotnet/MsRdpEx_Test/MsRdpEx_Test.csproj`	Configures interop tests.
`dotnet/MsRdpEx_Test/Compatibility.cs`	Tests legacy API compatibility.
`dotnet/MsRdpEx_Test/BinaryString.cs`	Tests binary-string semantics.
`dotnet/MsRdpEx_NativeAotInterop_Test/Program.cs`	Adds NativeAOT consumer checks.
`dotnet/MsRdpEx_NativeAotInterop_Test/MsRdpEx_NativeAotInterop_Test.csproj`	Configures NativeAOT publishing.
`dotnet/MsRdpEx_LegacyInterop_Test/Program.cs`	Adds legacy consumer fixture.
`dotnet/MsRdpEx_LegacyInterop_Test/MsRdpEx_LegacyInterop_Test.csproj`	Configures legacy package test.
`dotnet/MsRdpEx_Gen/Program.cs`	Adds interop source generator.
`dotnet/MsRdpEx_Gen/MsRdpEx_Gen.csproj`	Configures generator build.
`dotnet/MsRdpEx_App/RdpView.cs`	Adapts generated COM lifetimes.
`dotnet/MsRdpEx_App/Program.cs`	Disables default COM visibility.
`dotnet/MsRdpEx_App/MsRdpEx_App.csproj`	Uses generated interop projects.
`dotnet/MsRdpEx_App/MainDlg.cs`	Migrates calls to compatibility helpers.
`dotnet/Interop.MSTSCLib.Generated/Interop.MSTSCLib.Generated.csproj`	Builds standalone generated interop.
`dotnet/Interop.MSTSCLib.Generated.WinForms/Interop.MSTSCLib.Generated.WinForms.csproj`	Builds independent WinForms host.
`dotnet/Interop.MSTSCLib.Generated.WinForms/GeneratedRdpClientHost.cs`	Implements generated ActiveX hosting.
`dotnet/Devolutions.MsRdpEx/MarshalHelpers.cs`	Adds source-generated UTF-8 marshalling.
`dotnet/Devolutions.MsRdpEx/LoadBalanceInfo.cs`	Removes the legacy load-balance shim.
`dotnet/Devolutions.MsRdpEx/Devolutions.MsRdpEx.targets`	Adds package interop selection.
`dotnet/Devolutions.MsRdpEx/Devolutions.MsRdpEx.csproj`	Multi-targets and packages interop assets.
`dotnet/Devolutions.MsRdpEx/Bindings.cs`	Migrates native COM bindings.
`dotnet/CMakeLists.txt`	Includes new managed projects.
`dotnet/AxInterop.MSTSCLib/RdpAxHost.cs`	Adapts ActiveX hosting for generated COM.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/TransportSettings.cs`	Declares transport interfaces.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/Shell.cs`	Declares client-shell interfaces.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/SecuredSettings.cs`	Declares secured-settings interfaces.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/RemoteProgram.cs`	Declares RemoteApp interfaces.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/RemoteDesktopClient.cs`	Declares modern client interfaces.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/RedirectionInfo.cs`	Declares redirection settings.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/NonScriptableClient.cs`	Declares non-scriptable APIs.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/ExtendedSettings.cs`	Declares extended settings.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/Drive.cs`	Declares drive redirection APIs.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/Device.cs`	Declares device redirection APIs.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/Debug.cs`	Declares debug interfaces.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/Clipboard.cs`	Declares clipboard APIs.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/Client.cs`	Declares core RDP interfaces and events.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/Camera.cs`	Declares camera redirection APIs.
`dotnet/AxInterop.MSTSCLib/MSTSCLib/AdvancedSettings.cs`	Declares advanced settings.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/Variant.cs`	Implements VARIANT marshalling.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/RdpClientFactory.cs`	Adds typed COM activation.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/ProxyObject.cs`	Implements generated proxy wrapping.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/ProxyMetadata.cs`	Maps interfaces to proxies and IIDs.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/IDispatch.cs`	Declares generated IDispatch support.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/Extensions.cs`	Adds low-level interop adapters.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/BinaryStringRef.cs`	Adds borrowed binary BSTR support.
`dotnet/AxInterop.MSTSCLib/Interop/NetCore/BinaryString.cs`	Adds managed binary BSTR support.
`dotnet/AxInterop.MSTSCLib/Interop/Extensions.cs`	Adds compatibility extension methods.
`dotnet/AxInterop.MSTSCLib/Interop/Desktop/ProxyObject.cs`	Adds desktop proxy passthrough.
`dotnet/AxInterop.MSTSCLib/Interop/Desktop/Compatibility.cs`	Adds desktop compatibility attribute.
`dotnet/AxInterop.MSTSCLib/Interop/Desktop/BinaryString.cs`	Adds desktop binary BSTR support.
`dotnet/AxInterop.MSTSCLib/Interop/Compatibility.cs`	Adds classic event sink interfaces.
`dotnet/AxInterop.MSTSCLib/Interop/BinaryString.cs`	Adds classic custom marshaller.
`dotnet/AxInterop.MSTSCLib/Generated/Enums.cs`	Adds generated legacy-compatible enums.
`dotnet/AxInterop.MSTSCLib/AxInterop.MSTSCLib.csproj`	Configures generated WinForms interop.
`dotnet/AxInterop.MSTSCLib.Legacy/RdpAxHost.Legacy.cs`	Preserves legacy ActiveX hosting.
`dotnet/AxInterop.MSTSCLib.Legacy/AxInterop.MSTSCLib.Legacy.csproj`	Builds legacy interop assemblies.
`.github/workflows/build-package.yml`	Validates package consumers and PE payloads.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

+            public static nint ConvertToUnmanaged(BinaryStringRef value)
+            {
+                fixed (byte* pointer = value.content)
+                    return BinaryStringInterop.AllocateByteBuffer(pointer, value.content.Length);


+                nint result;
+                if (data.mTextData is not null)
+                {
+                    fixed (char* pTextData = data.mTextData)
+                        result = BinaryStringInterop.AllocateTextBuffer(pTextData, data.mTextData.Length);
+                }
+                else if (!data.mByteData.IsDefault)
+                {
+                    fixed (byte* pByteData = data.mByteData.AsSpan())
+                        result = BinaryStringInterop.AllocateByteBuffer(pByteData, data.mByteData.Length);
+                }
+                else throw new UnreachableException();


Tobias Käs (weltkante) · 2026-07-22T21:00:56Z

+                default:
+                    throw new NotSupportedException();


where is GetPublisherCertificateChain appearing? I couldn't find it with a quick search. I'd double check this claim before bothering with it, during my tests I didn't run into the exception (or I'd have added the missing cases)

It is declared as IMsRdpClientNonScriptable4.GetPublisherCertificateChain in dotnet/AxInterop.MSTSCLib/MSTSCLib/NonScriptableClient.cs and called by the generated redirection adapter. The VARIANT marshaller now round-trips the expected VT_ARRAY | VT_UI1 payload as byte[]; this also supports SetPublisherCertificateChain.

+                    return ProxyObject.Pack(ComInterfaceMarshaller<object>.ConvertToManaged((void*)data.Content1));
+
+                case VariantType.ByRefModifier | VariantType.Error: return *(int*)data.Content1;
+                case VariantType.ByRefModifier | VariantType.Boolean: return *(short*)data.Content1;


+                case VariantType.ByRefModifier | VariantType.Currency: return *(long*)data.Content1;
+                case VariantType.ByRefModifier | VariantType.DateTime: return *(double*)data.Content1;


+    <Error Condition="'$(MsRdpExComInterop)' == 'Generated' And !Exists('$(_MsRdpExGeneratedInteropPath)')"
+           Text="MsRdpExComInterop=Generated requires '$(_MsRdpExGeneratedInteropPath)', but the selected Devolutions.MsRdpEx package does not contain it. Select a package with MsRdpExGeneratedInteropSupported=true or use Legacy." />


+          dotnet test .\dotnet\MsRdpEx_Test\MsRdpEx_Test.csproj -c Release -p:CMakeOutputPath="$BuildDir\Release" -v:minimal
+          dotnet run --project .\dotnet\MsRdpEx_LegacyInterop_Test\MsRdpEx_LegacyInterop_Test.csproj -c Release -p:MsRdpExTestPackageSource="$PackageSource" -p:MsRdpExPackageVersion="$PackageVersion" --no-launch-profile
+          dotnet publish .\dotnet\MsRdpEx_NativeAotInterop_Test\MsRdpEx_NativeAotInterop_Test.csproj -c Release -o .\nativeaot-test -p:MsRdpExTestPackageSource="$PackageSource" -p:MsRdpExPackageVersion="$PackageVersion" -v:minimal
+          & .\nativeaot-test\MsRdpEx_NativeAotInterop_Test.exe


Preserve legacy NuGet interop as the default while adding source-generated COM projections, NativeAOT support, generated WinForms hosting, consumer validation, and compatibility tests. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

…175) #173 removed this hand-written declaration along with the rest of the manual interop surface — the generated interop types `LoadBalanceInfo` as `BinaryString` and no longer needs it. But legacy-interop consumers on the current package lose their only way to set a byte-exact `LoadBalanceInfo`. Restored verbatim from `2026.7.3`, relocated into `AxInterop.MSTSCLib.Legacy` so it ships in the legacy interop assembly and `Devolutions.MsRdpEx` stays MSTSCLib-free. Context: lets RDM bump to the current package (recording-cursor fix, #174) while staying on the legacy interop, without carrying this declaration itself. Verified against RDM: builds clean, `LoadBalanceInfo` path unchanged.

Marc-André Moreau (mamoreau-devolutions) requested a review from a team as a code owner July 22, 2026 18:34

Copilot started work on behalf of Marc-André Moreau (mamoreau-devolutions) July 22, 2026 19:01 View session

Copilot AI review requested due to automatic review settings July 22, 2026 19:05

Copilot started reviewing on behalf of Marc-André Moreau (mamoreau-devolutions) July 22, 2026 19:06 View session

Copilot finished work on behalf of Marc-André Moreau (mamoreau-devolutions) July 22, 2026 19:09

Copilot AI reviewed Jul 22, 2026

View reviewed changes

Marc-André Moreau (mamoreau-devolutions) force-pushed the com-interop branch 3 times, most recently from d435375 to 4d3c30c Compare July 22, 2026 20:47

Marc-André Moreau (mamoreau-devolutions) force-pushed the com-interop branch from 4d3c30c to 4547687 Compare July 23, 2026 00:30

Marc-André Moreau (mamoreau-devolutions) and others added 4 commits July 22, 2026 21:34

Validate NativeAOT COM integration

58211e2

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Add legacy event argument aliases

284308c

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Share generated WinForms interop types

183c08b

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Fix generated WinForms host activation

245962f

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Marc-André Moreau (mamoreau-devolutions) merged commit eea4cf8 into master Jul 23, 2026

irvingouj@Devolutions (irvingoujAtDevolution) mentioned this pull request Jul 24, 2026

Restore IMsRdpClientAdvancedSettingsLB for legacy interop consumers #175

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Add modern COM interop support#173

Add modern COM interop support#173
Marc-André Moreau (mamoreau-devolutions) merged 5 commits into
masterfrom
com-interop

Marc-André Moreau (mamoreau-devolutions) commented Jul 22, 2026

Uh oh!

Marc-André Moreau (mamoreau-devolutions) commented Jul 22, 2026

Uh oh!

Copilot AI commented Jul 22, 2026

Uh oh!

Copilot AI left a comment

Uh oh!

Tobias Käs (weltkante) Jul 22, 2026

Uh oh!

Marc-André Moreau (mamoreau-devolutions) Jul 23, 2026

Uh oh!

Reviewers

Assignees

Labels

Milestone

Development

Uh oh!

4 participants

		case VariantType.ByRefModifier \| VariantType.Currency: return (long)data.Content1;
		case VariantType.ByRefModifier \| VariantType.DateTime: return (double)data.Content1;

		<Error Condition="'$(MsRdpExComInterop)' == 'Generated' And !Exists('$(_MsRdpExGeneratedInteropPath)')"
		Text="MsRdpExComInterop=Generated requires '$(_MsRdpExGeneratedInteropPath)', but the selected Devolutions.MsRdpEx package does not contain it. Select a package with MsRdpExGeneratedInteropSupported=true or use Legacy." />

Uh oh!

Conversation

Marc-André Moreau (mamoreau-devolutions) commented Jul 22, 2026

Summary

Credit

Uh oh!

Marc-André Moreau (mamoreau-devolutions) commented Jul 22, 2026

Uh oh!

Copilot AI commented Jul 22, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Tobias Käs (weltkante) Jul 22, 2026

Choose a reason for hiding this comment

Uh oh!

Marc-André Moreau (mamoreau-devolutions) Jul 23, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Milestone

Development

Uh oh!

4 participants