How to load assemblies from file in dotnet core 1.1

Question

My project was on dotnet core 1.0 and I used the below line to load assemblies from files, and it was working fine.

assembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(file.FullName);

Now I update my project to dotnet core 1.1,and I get below exception

System.IO.FileLoadException: Could not load file or assembly 'PartyManagement, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. at System.Runtime.Loader.AssemblyLoadContext.LoadFromPath(IntPtr ptrNativeAssemblyLoadContext, String ilPath, String niPath, ObjectHandleOnStack retAssembly) at System.Runtime.Loader.AssemblyLoadContext.LoadFromAssemblyPath(String assemblyPath) at Tuba.Framework.Builder.MetaDataDirector.Build() in C:\projects\Tuba\Tuba\src\Framework\Tuba.Framework\Builder\MetaDataDirector.cs:line 36