Could not load file or assembly 'System.Net.Http'

[zkost]

I've been using Twilio for many years. Awesome product and service! When it works, it works reliably, when it breaks it breaks reliably. I'm not sure if this is a Twilio issue or a Twilio symptom considering the many, many .net changes going on.

Version:
vs2017 15.7.5
.Net 4.7.2 (version 4.7.03056)
Twilio 5.14.1.0

Code Snippet

      string _fromNumber = "+1....";
      string _accountSid = "....";
      string _authToken = "....";

      // Find your Account Sid and Auth Token at twilio.com/console
      TwilioClient.Init(_accountSid, _authToken);

      CreateMessageOptions sms = new CreateMessageOptions(new Twilio.Types.PhoneNumber("+1...."))
      {
        From = new Twilio.Types.PhoneNumber(_fromNumber),

        // only send the first 160 characters of a message.
        Body = "Test"
      };
	  // this next line of code is where the exception is thrown
      MessageResource.Create(sms);

Exception/Log

An unhandled exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll
Additional information: Could not load file or assembly 'System.Net.Http, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

Steps to Reproduce

1. Blank new project. Set to 4.7.2, install Twilio 5.14.1.0 and download dependencies from nuget
2. Run the above code and you get the exception. I confirm that System.net.http verson

My app.config

<runtime>
   ....
         <dependentAssembly>
            <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
            <bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.2.0.0" />
         </dependentAssembly>

Considerations:

1. First guess is that there is a reference issue in Twilio.dll 5.14.1.0 when running 4.7.2
2. Twilio 5.14.1.0 is not compatible with Net 4.7.2
3. The exception is a red herring for some other exception not bubbling up.
4. This very well be within my code, but I can't make it any more vanilla.

Is anyone else experiencing this or similiar issue? For me downgrading is not an option. Any insight is greatly appreciated.

[dsghi]

Where did the System.Net.Http binding redirect come from in your app.config? The redirect is not part of a 4.7 console app or blank web application template nor is it added by the Twilio package. I would suggest taking that out and trying without it...

Here's what I have with a blank console app and the Twilio package:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7" />
    </startup>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-11.0.0.0" newVersion="11.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.IdentityModel.Tokens.Jwt" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.IdentityModel.Tokens" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-5.2.4.0" newVersion="5.2.4.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

[zkost]

Derek,

I was asking the wrong question. I was chasing why "System.Net.Http" cannot be found rather then why is it there in the first place. That was my issue. I removed the reference from my app.config and all is working.

Now the question is how did 'System.Net.Http' it get into my app.config? I must have unknowingly added it or it was done as part of a nuget update. I'm betting and hoping it was me; in either case it's not an issue for Twilio.

Issue Closed.

Thanks for the nudge in the right direction.
-Ben