RegAsm failing for a .NET 4.0 assembly using Microsoft.Bcl.Async

Question

RegAsm failing for a .NET 4.0 assembly using Microsoft.Bcl.Async with the following message:

RegAsm : error RA0000 : Could not load file or assembly 
'System.Threading.Tasks, Version=1.5.11.0, Culture=neutral, 
PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. 
The located assembly's manifest definition does not match 
the assembly reference. (Exception from HRESULT: 0x80131040)

My assembly (MyAssembly.dll) uses the latest Microsoft.Bcl.Async NuGet package, here's the project's packages.config:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Microsoft.Bcl" version="1.1.6" targetFramework="net40" />
  <package id="Microsoft.Bcl.Async" version="1.0.165" targetFramework="net40" />
  <package id="Microsoft.Bcl.Build" version="1.0.13" targetFramework="net40" />
</packages>

It bundles System.Threading.Tasks.dll Version: 2.6.6.0 which is a part of that NuGet package. There is no other System.Threading.Tasks.dll on the target system (Win7 with .NET 4.0 but without .NET 4.5), neither in GAC nor anywhere else.

Here is MyAssembly.dll.config, it has correct bindingRedirect elements for System.Threading.Tasks:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.IO" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.6.6.0" newVersion="2.6.6.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.6.6.0" newVersion="2.6.6.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Threading.Tasks" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.6.6.0" newVersion="2.6.6.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

My question: does RegAsm not use MyAssembly.dll.config? How do I make it work so it resolves bindingRedirect instructions?

Answer 1

The solution I have come up with is a hack:

• copied RegAsm.exe and RegAsm.exe.config from C:\Windows\Microsoft.NET\Framework\v4.0.30319\RegAsm.exe to a local folder where MyAssembly.dll is;

• edited RegAsm.exe.config to look like this:

<?xml version ="1.0"?>
<configuration>
    <startup useLegacyV2RuntimeActivationPolicy="true">
        <requiredRuntime safemode="true" imageVersion="v4.0.30319" version="v4.0.30319"/>
        <supportedRuntime version="v4.0" sku="client" />
    </startup>

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.IO" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.6.6.0" newVersion="2.6.6.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.6.6.0" newVersion="2.6.6.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Threading.Tasks" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.6.6.0" newVersion="2.6.6.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

</configuration>

• now, running RegAsm.exe /codebase MyAssembly.dll works fine as expected.

Interestingly, useLegacyV2RuntimeActivationPolicy="true" has already been there in the standard RegAsm.exe.config, but alone it did not help.

I think this is the same bug reported here: https://connect.microsoft.com/VisualStudio/feedback/details/789318/asyncpack-system-io-fileloadexception-could-not-load-file-or-assembly-system-threading-tasks-version-1-5-11-0.