System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.EntityFrameworkCore, Version=2.2.0.0,

Question

I created a .net core 2.2 project using the AWS Lambda function template. Added a MySQL EntityFramework nuget package. My project targets .NET Core 2.2. I have code which uses DbContext and EF stuff. When I run the app using their lambda test tool, I get this error: System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.EntityFrameworkCore, Version=2.2.0.0, .....

Using Process Monitor, I can see the app is trying to load Microsoft.EntityFrameworkCore.dll from ...\bin\Debug\netcoreapp2.2\Microsoft.EntityFrameworkCore.dll which doesn't exist.

My question is why aren't any of the supporting assemblies in that folder? The only assembly (.dll file) in the folder is my app's.

Answer 1

Following step help you to solve this problem:

1. Delete all bin and obj folders.
2. Clean Solution. [Build>Clean Solution].
3. Rebuild Solution

Answer 2

Try to use some type of Microsoft.EntityFrameworkCore namespace explicitly somewhere in your code. For example:

var _ = new Microsoft.EntityFrameworkCore.DbContextOptionsBuilder();

It sould force the build to copy the assembly to result directory.

Answer 3

I have some ideas. Firstly check, if the folder that you want to refer allows the Visual to have access.

If it do not work, try reinstaling packages through nugget (If I remember correctly I had this same error.). If it shows that its not installed in nugget manager, just install it, even a few times.

Here is the anwser for your question at the end: Where does NuGet put the dll?

Answer 4

I had a similar problem, in my case removing the line from the .csproj file helped

<PublishReadyToRun>true</PublishReadyToRun>