Add Reactor (Microsoft.UI.Reactor) dotnet new templates

.gitignore

@@ -403,3 +403,6 @@ build/override/
 # WindowsAppSDK specific files
 Microsoft.WinUI.AppX.targets
 !dev/vsix/**/*.pubxml
+# Project templates ship publish profiles as template content, so they must be
+# committed despite the blanket *.pubxml rule above.
+!dev/Templates/**/*.pubxml

build/AzurePipelinesTemplates/WindowsAppSDK-DotnetNewTemplates-Test-Stage.yml

@@ -26,6 +26,12 @@ parameters:
 - name: dotnetSdkVersion
   type: string
   default: '8.0.x'
+# Reactor project templates target net10.0 and declare a [10.0,) SDK
+# constraint, so the test agent also needs the .NET 10 SDK to scaffold and
+# build them. Installed alongside dotnetSdkVersion below.
+- name: reactorDotnetSdkVersion
+  type: string
+  default: '10.0.x'
 - name: WindowsAppSdkVersion
   type: string
   default: '*'
@@ -68,6 +74,16 @@ stages:
         packageType: sdk
         version: '${{ parameters.dotnetSdkVersion }}'
 
+    # Reactor templates require the .NET 10 SDK (they target net10.0 and set a
+    # [10.0,) sdk-version constraint). Install it alongside the version above;
+    # the .NET muxer picks the highest installed SDK, and the WinUI templates
+    # auto-detect their TFM and build cleanly on .NET 10 as well.
+    - task: UseDotNet@2
+      displayName: 'Use .NET SDK ${{ parameters.reactorDotnetSdkVersion }} (for Reactor templates)'
+      inputs:
+        packageType: sdk
+        version: '${{ parameters.reactorDotnetSdkVersion }}'
+
     - task: NuGetAuthenticate@1
       displayName: 'Authenticate NuGet feeds'
 

dev/Templates/Dotnet/README.md

@@ -34,6 +34,40 @@ Get below list via `dotnet new list winui`
 
 Each `winui-*` short name also has a `winui3-*` alias (e.g. `winui3-mvvm`).
 
+### Reactor Templates (Experimental)
+
+> [!IMPORTANT]
+> These templates are **experimental**.
+> [Microsoft.UI.Reactor](https://github.com/microsoft/microsoft-ui-reactor) is
+> prerelease software: its API may change in breaking ways between releases, and
+> these templates may change or be removed. They aren't recommended for
+> production apps yet.
+
+[Microsoft.UI.Reactor](https://github.com/microsoft/microsoft-ui-reactor) is a
+declarative, React-style way to build WinUI 3 apps in **pure C# — no XAML**.
+These templates scaffold a runnable, single-project MSIX-packaged Reactor app
+whose UI mirrors the matching WinUI 3 XAML templates.
+
+Get the list via `dotnet new list reactor`
+
+| Short Name         | Description                                                          |
+|--------------------|----------------------------------------------------------------------|
+| `reactor`          | Blank Reactor app (alias `reactor-blank`). Start here if unsure      |
+| `reactor-mvu`      | Reactor app using the Model-View-Update pattern with `UseReducer`    |
+| `reactor-navview`  | Reactor app with a `NavigationView` shell and multiple pages         |
+| `reactor-tabview`  | Reactor app with a `TabView` shell whose tabs live in the title bar  |
+
+Each also has a `winui-reactor*` alias (e.g. `winui-reactor`, `winui-reactor-mvu`)
+so they show up under `dotnet new list winui` alongside the other WinUI templates.
+
+Reactor apps are packaged (single-project MSIX) and reference the
+[`Microsoft.UI.Reactor`](https://www.nuget.org/packages/Microsoft.UI.Reactor)
+preview NuGet package. They require .NET 10 or later. Like the WinUI templates,
+they reference `Microsoft.Windows.SDK.BuildTools.WinApp` so `dotnet run` launches
+the app with full MSIX package identity. Pin a specific Reactor package version
+at scaffold time with `--reactor-version`, or the Windows App SDK version with
+`--wasdk-version`.
+
 ### Item Templates
 
 | Short Name                 | Description                                              |
@@ -64,6 +98,22 @@ dotnet run
 `dotnet run` registers a loose-layout MSIX, gives the app package identity,
 and launches it via AUMID activation — equivalent to F5 in Visual Studio.
 
+### Quickstart a new Reactor app
+
+```powershell
+dotnet new reactor -n MyReactorApp
+cd MyReactorApp
+dotnet run
+```
+
+Reactor apps are pure C# (no XAML) and packaged (single-project MSIX), so
+`dotnet run` registers a loose-layout package and launches the app with full
+MSIX package identity — equivalent to F5 in Visual Studio. See the
+[Reactor documentation](https://github.com/microsoft/microsoft-ui-reactor) to
+learn the component model, hooks, and layout system. Swap `reactor` for
+`reactor-mvu`, `reactor-navview`, or `reactor-tabview` to start from a richer
+shell.
+
 ### Add items to an existing project
 
 ```powershell

dev/Templates/Dotnet/Test-DotnetNewTemplates.ps1

@@ -599,7 +599,14 @@ try {
         # acquires package identity) via UnitTestClient.Run(), not via
         # `dotnet test`. Validate it as an App so we still confirm the
         # template builds cleanly.
-        @{ ShortName = 'winui-unittest'; Kind = 'App' }
+        @{ ShortName = 'winui-unittest'; Kind = 'App' },
+        # Reactor (Microsoft.UI.Reactor) app templates: pure C#, unpackaged,
+        # dotnet-new-only. They build with the same App path below
+        # (-p:WindowsPackageType=None), and their .csproj already sets it.
+        @{ ShortName = 'reactor'; Kind = 'App' },
+        @{ ShortName = 'reactor-mvu'; Kind = 'App' },
+        @{ ShortName = 'reactor-navview'; Kind = 'App' },
+        @{ ShortName = 'reactor-tabview'; Kind = 'App' }
     )
 
     foreach ($template in $projectTemplates) {

dev/Templates/Dotnet/templates/reactor-blank-app/.template.config/dotnetcli.host.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "https://json.schemastore.org/dotnetcli.host",
+  "symbolInfo": {
+    "dotnetVersion": {
+      "longName": "dotnet-version",
+      "shortName": "tfm",
+      "description": "Base TFM for the project (Microsoft.UI.Reactor requires net10.0 or later)."
+    },
+    "reactorVersion": {
+      "longName": "reactor-version",
+      "shortName": "rv",
+      "description": "Pin to a specific Microsoft.UI.Reactor NuGet version."
+    },
+    "windowsAppSdkVersion": {
+      "longName": "wasdk-version",
+      "shortName": "wasdkv",
+      "description": "Pin to a specific Windows App SDK NuGet version."
+    },
+    "skipRestore": {
+      "longName": "no-restore",
+      "shortName": ""
+    }
+  }
+}

dev/Templates/Dotnet/templates/reactor-blank-app/.template.config/ide.host.json

@@ -0,0 +1,33 @@
+{
+  "icon": "icon.png",
+  "requiredComponents": [
+    {
+      "id": "Microsoft.VisualStudio.Workload.ManagedDesktop",
+      "hostId": "vs",
+      "componentType": "setupComponent"
+    }
+  ],
+  "symbolInfo": [
+    {
+      "id": "dotnetVersion",
+      "name": {
+        "text": "Framework"
+      },
+      "isVisible": "true"
+    },
+    {
+      "id": "reactorVersion",
+      "name": {
+        "text": "Microsoft.UI.Reactor version"
+      },
+      "isVisible": "true"
+    },
+    {
+      "id": "windowsAppSdkVersion",
+      "name": {
+        "text": "Windows App SDK version"
+      },
+      "isVisible": "true"
+    }
+  ]
+}

dev/Templates/Dotnet/templates/reactor-blank-app/.template.config/template.json

@@ -0,0 +1,145 @@
+{
+  "$schema": "https://json.schemastore.org/template",
+  "author": "Microsoft",
+  "classifications": [ "Windows", "WinUI", "Desktop", "Reactor", "Experimental" ],
+  "tags": {
+    "language": "C#",
+    "type": "project"
+  },
+  "identity": "Microsoft.WindowsAppSDK.Reactor.CSharp.BlankApp",
+  "groupIdentity": "Microsoft.WindowsAppSDK.Reactor.CSharp.BlankApp",
+  "name": "Reactor Blank App (Experimental)",
+  "shortName": [ "reactor", "reactor-blank", "winui-reactor" ],
+  "sourceName": "ProjectTemplate",
+  "defaultName": "ReactorApp",
+  "description": "Experimental. Creates a blank Microsoft.UI.Reactor (WinUI 3) desktop app. Pure C#, no XAML. Start here if unsure. Microsoft.UI.Reactor is prerelease and its API may change.",
+  "preferNameDirectory": true,
+  "constraints": {
+    "windows-only": {
+      "type": "os",
+      "args": "Windows"
+    },
+    "sdk-version": {
+      "type": "sdk-version",
+      "args": [ "[10.0,)" ]
+    }
+  },
+  "symbols": {
+    "safeProjectName": {
+      "type": "derived",
+      "valueSource": "name",
+      "valueTransform": "safe_name",
+      "replaces": "$safeprojectname$"
+    },
+    "projectName": {
+      "type": "derived",
+      "valueSource": "name",
+      "valueTransform": "identity",
+      "replaces": "$projectname$"
+    },
+    "dotnetVersion": {
+      "type": "parameter",
+      "datatype": "choice",
+      "description": "Base target framework moniker (TFM). Microsoft.UI.Reactor requires .NET 10 or later.",
+      "choices": [
+        { "choice": "net10.0", "description": "Target .NET 10" }
+      ],
+      "defaultValue": "net10.0",
+      "replaces": "$DotNetVersion$"
+    },
+    "reactorVersion": {
+      "type": "parameter",
+      "datatype": "text",
+      "defaultValue": "0.1.0-preview.13",
+      "replaces": "$ReactorVersion$",
+      "description": "Microsoft.UI.Reactor (and Microsoft.UI.Reactor.Devtools) NuGet version to reference."
+    },
+    "windowsAppSdkVersion": {
+      "type": "parameter",
+      "datatype": "text",
+      "defaultValue": "*",
+      "replaces": "$WindowsAppSdkVersion$",
+      "description": "Microsoft.WindowsAppSDK NuGet version. Requires 2.1.3 or later; use * for the latest stable."
+    },
+    "windowsSdkBuildToolsVersion": {
+      "type": "parameter",
+      "datatype": "text",
+      "defaultValue": "*",
+      "replaces": "$WindowsSdkBuildToolsVersion$",
+      "description": "Microsoft.Windows.SDK.BuildTools NuGet version. Use * for the latest stable."
+    },
+    "windowsSdkBuildToolsWinAppVersion": {
+      "type": "parameter",
+      "datatype": "text",
+      "defaultValue": "*",
+      "replaces": "$WindowsSdkBuildToolsWinAppVersion$",
+      "description": "Microsoft.Windows.SDK.BuildTools.WinApp NuGet version. Use * for the latest stable."
+    },
+    "publisherDn": {
+      "type": "parameter",
+      "datatype": "text",
+      "replaces": "$XmlEscapedPublisherDistinguishedName$",
+      "defaultValue": "CN=AppPublisher",
+      "description": "Publisher distinguished name used inside Package.appxmanifest."
+    },
+    "publisherDisplay": {
+      "type": "parameter",
+      "datatype": "text",
+      "replaces": "$XmlEscapedPublisher$",
+      "defaultValue": "AppPublisher",
+      "description": "Publisher display name shown in the manifest."
+    },
+    "guid9": {
+      "type": "generated",
+      "generator": "guid",
+      "parameters": {
+        "format": "D"
+      },
+      "replaces": "$guid9$"
+    },
+    "skipRestore": {
+      "type": "parameter",
+      "datatype": "bool",
+      "defaultValue": "false",
+      "description": "If specified, skips the automatic restore of the project on create."
+    }
+  },
+  "sources": [
+    {
+      "modifiers": [
+        {
+          "replacements": [
+            {
+              "before": "$targetnametoken$",
+              "after": "{{safeProjectName}}"
+            }
+          ]
+        }
+      ],
+      "rename": {
+        "gitignore.txt": ".gitignore"
+      }
+    }
+  ],
+  "primaryOutputs": [
+    { "path": "ProjectTemplate.csproj" }
+  ],
+  "forms": {
+    "safe_name": {
+      "identifier": "safe_name"
+    },
+    "identity": {
+      "identifier": "identity"
+    }
+  },
+  "postActions": [
+    {
+      "id": "restore",
+      "condition": "(!skipRestore)",
+      "actionId": "210D431B-A78B-4D2F-B762-4ED3E3EA9025",
+      "continueOnError": true,
+      "description": "Restore NuGet packages required by this project.",
+      "manualInstructions": [ { "text": "Run 'dotnet restore'" } ]
+    }
+  ]
+}

dev/Templates/Dotnet/templates/reactor-mvu-app/.template.config/dotnetcli.host.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "https://json.schemastore.org/dotnetcli.host",
+  "symbolInfo": {
+    "dotnetVersion": {
+      "longName": "dotnet-version",
+      "shortName": "tfm",
+      "description": "Base TFM for the project (Microsoft.UI.Reactor requires net10.0 or later)."
+    },
+    "reactorVersion": {
+      "longName": "reactor-version",
+      "shortName": "rv",
+      "description": "Pin to a specific Microsoft.UI.Reactor NuGet version."
+    },
+    "windowsAppSdkVersion": {
+      "longName": "wasdk-version",
+      "shortName": "wasdkv",
+      "description": "Pin to a specific Windows App SDK NuGet version."
+    },
+    "skipRestore": {
+      "longName": "no-restore",
+      "shortName": ""
+    }
+  }
+}

dev/Templates/Dotnet/templates/reactor-mvu-app/.template.config/ide.host.json

@@ -0,0 +1,33 @@
+{
+  "icon": "icon.png",
+  "requiredComponents": [
+    {
+      "id": "Microsoft.VisualStudio.Workload.ManagedDesktop",
+      "hostId": "vs",
+      "componentType": "setupComponent"
+    }
+  ],
+  "symbolInfo": [
+    {
+      "id": "dotnetVersion",
+      "name": {
+        "text": "Framework"
+      },
+      "isVisible": "true"
+    },
+    {
+      "id": "reactorVersion",
+      "name": {
+        "text": "Microsoft.UI.Reactor version"
+      },
+      "isVisible": "true"
+    },
+    {
+      "id": "windowsAppSdkVersion",
+      "name": {
+        "text": "Windows App SDK version"
+      },
+      "isVisible": "true"
+    }
+  ]
+}