Get the correct version of Mvc for multitargeting

src/Microsoft.VisualStudio.LanguageServices.Razor/DefaultTemplateEngineFactoryService.cs

@@ -2,7 +2,10 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.IO;
+using System.Linq;
 using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.Host;
 using Mvc1_X = Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X;
 using MvcLatest = Microsoft.AspNetCore.Mvc.Razor.Extensions;
@@ -11,6 +14,7 @@ namespace Microsoft.CodeAnalysis.Razor
 {
     internal class DefaultTemplateEngineFactoryService : RazorTemplateEngineFactoryService
     {
+        private const string MvcAssemblyName = "Microsoft.AspNetCore.Mvc.Razor";
         private static readonly Version LatestSupportedMvc = new Version(2, 1, 0);
 
         private readonly HostLanguageServices _services;
@@ -70,8 +74,36 @@ namespace Microsoft.CodeAnalysis.Razor
 
         private Version GetMvcVersion(string projectPath)
         {
-            // TODO: Need to figure out the actual referenced Mvc version in the project. https://github.com/aspnet/Razor/issues/1183
+            var workspace = _services.WorkspaceServices.Workspace;
+
+            var project = workspace.CurrentSolution.Projects.FirstOrDefault(p =>
+            {
+                var directory = Path.GetDirectoryName(p.FilePath);
+                return string.Equals(
+                    NormalizeDirectoryPath(directory),
+                    NormalizeDirectoryPath(projectPath),
+                    StringComparison.OrdinalIgnoreCase);
+            });
+
+            if (project != null)
+            {
+                var compilation = CSharpCompilation.Create(project.AssemblyName).AddReferences(project.MetadataReferences);
+
+                foreach (var identity in compilation.ReferencedAssemblyNames)
+                {
+                    if (identity.Name == MvcAssemblyName)
+                    {
+                        return identity.Version;
+                    }
+                }
+            }
+
             return null;
         }
+
+        private string NormalizeDirectoryPath(string path)
+        {
+            return path.Replace('\\', '/').TrimEnd('/');
+        }
     }
 }

tooling/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.csproj

@@ -153,6 +153,14 @@
       <IncludeOutputGroupsInVSIXLocalOnly>
       </IncludeOutputGroupsInVSIXLocalOnly>
     </ProjectReference>
+    <ProjectReference Include="..\..\src\Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X\Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X.csproj">
+      <Name>Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X</Name>
+      <Private>False</Private>
+      <IncludeOutputGroupsInVSIX>
+      </IncludeOutputGroupsInVSIX>
+      <IncludeOutputGroupsInVSIXLocalOnly>
+      </IncludeOutputGroupsInVSIXLocalOnly>
+    </ProjectReference>
     <ProjectReference Include="..\..\src\Microsoft.AspNetCore.Razor.Language\Microsoft.AspNetCore.Razor.Language.csproj">
       <Project>{932f3c9c-a6c0-40d3-ba50-9309886242fc}</Project>
       <Name>Microsoft.AspNetCore.Razor.Language</Name>
@@ -246,6 +254,7 @@
   <ItemGroup>
     <VSIXSourceItem Include="..\..\src\Microsoft.CodeAnalysis.Remote.Razor\bin\$(Configuration)\net46\Microsoft.CodeAnalysis.Remote.Razor.dll" />
     <VSIXSourceItem Include="..\..\src\Microsoft.AspNetCore.Mvc.Razor.Extensions\bin\$(Configuration)\net46\Microsoft.AspNetCore.Mvc.Razor.Extensions.dll" />
+    <VSIXSourceItem Include="..\..\src\Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X\bin\$(Configuration)\net46\Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X.dll" />
     <VSIXSourceItem Include="..\..\src\Microsoft.VisualStudio.LanguageServices.Razor\bin\$(Configuration)\net46\Microsoft.AspNetCore.Razor.Language.dll" />
     <VSIXSourceItem Include="..\..\src\Microsoft.VisualStudio.LanguageServices.Razor\bin\$(Configuration)\net46\Microsoft.CodeAnalysis.Razor.dll" />
     <VSIXSourceItem Include="..\..\src\Microsoft.VisualStudio.LanguageServices.Razor\bin\$(Configuration)\net46\Microsoft.CodeAnalysis.Razor.Workspaces.dll" />

tooling/Microsoft.VisualStudio.RazorExtension/Properties/BindingRedirectAttributes.cs

@@ -11,6 +11,14 @@ using Microsoft.VisualStudio.Shell;
     OldVersionUpperBound = "2.1.0.0",
     NewVersion = "2.1.0.0")]
 
+[assembly: ProvideBindingRedirection(
+    AssemblyName = "Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X",
+    GenerateCodeBase = true,
+    PublicKeyToken = "adb9793829ddae60",
+    OldVersionLowerBound = "0.0.0.0",
+    OldVersionUpperBound = "2.1.0.0",
+    NewVersion = "2.1.0.0")]
+
 [assembly: ProvideBindingRedirection(
     AssemblyName = "Microsoft.AspNetCore.Razor.Language",
     GenerateCodeBase = true,

tooling/Microsoft.VisualStudio.RazorExtension/source.extension.vsixmanifest

@@ -24,6 +24,7 @@
     <Asset Type="Microsoft.VisualStudio.MefComponent" d:Source="Project" d:ProjectName="%CurrentProject%" Path="|%CurrentProject%|" />
     <Asset Type="Microsoft.ServiceHub.Service" d:Source="File" Path="razorLanguageService.servicehub.service.json" />
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="Microsoft.AspNetCore.Mvc.Razor.Extensions.dll" />
+    <Asset Type="Microsoft.VisualStudio.Assembly" Path="Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X.dll" />
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="Microsoft.AspNetCore.Razor.Language.dll" />
     <Asset Type="Microsoft.VisualStudio.MefComponent" Path="Microsoft.AspNetCore.Razor.Language.dll" />
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="Microsoft.CodeAnalysis.Razor.dll" />