. Net core stepping on the pit practice

.net core Step on the pit

0. Error message

To be exact, there are two pits , One about .net core Version of , Another one about compilation options . First post the error message .

0.1 Unable to open the project

The first mistake is not to start the project , I put it on VS2017, When opening an existing project , Report errors Project file is incomplete. Expected imports are missing
But this project is git In the database , All products use this . Why can't I open it locally ？

0.2 Project cannot be loaded

The same environment , Another project , There's a project, In the open sln after , This project The display is not loaded normally , stay error list Middle tip ：
Error NU1105 Unable to find project information - The project file may be invalid or missing targets required for restore
And only this project cannot be loaded ,sln Others in the can .

0.3 System.BadImageFormatException

This problem is solved after the previous problem , Finally, I can open the compilation , But when it runs, it reports an error somewhere , This is this. System.BadImageFormatException

1 The first pit

1.1 VS edition

After consulting colleagues , He didn't find the reason , But he asked me that you didn't pretend vs2019 ah . I tried it on vs2019, And then I found out vs2019 Be able to open this project , Everything is all right , Use... Again vs2017 I can't open it .

1.2 .net core edition

Search for , Some people mentioned that .net core Why . Reviewed the instructions of the installation environment , It is required to follow .net core 2.1, I checked , Is, indeed, .net core 2.1 ah .
Later, I finally found a key place .
https://stackoverflow.com/questions/49432666/project-file-is-incomplete-expected-imports-are-missing
and
https://stackoverflow.com/questions/53329290/net-core-2-2-cant-be-selected-in-visual-studio-build-framework/55529011#55529011
Look at the instructions ：
Issue details: 2.1.6xx & 2.2.2xx version of the sdks are only supported on Visual Studio 2019. VS 2017 needs 2.1.5xx & 2.2.1xx versions of the sdk.

Check my installed .net core edition 2.1.818, I want to see others .net core 2.1 Download interface

above 2.1.818 Of visual studio support Is written 2019, Below 2.1.526 It's support vs2017 Of .
uninstall 2.1.818, install 2.1.526, VS2017 The project can be opened normally .
above 0.1 and 0.2 We've solved all our problems .

2. The second pit

2.1 x86

Compile successfully , debugging , However, an exception is thrown when running to a place where another library is called , This is this. System.BadImageFormatException, Search discovery , Usually because X86 and X64 Caused by the mixing of libraries . I know that other libraries use X86, I looked at the platform I chose when compiling , yes X86 ah

2.2 Find clues

How did you find the problem later ？ I am here attach to process When , There's a column of type It doesn't show all , I'll widen this column , It's all displayed , It says managed(V4.0.3xxx) X64.
What's going on? , What I chose was x86 ah ,
A light configure manager,

It's so deceptive ,active solution platform The choice is x86, But each project chose any cpu, So the last one is x64 Of .

Change to x86, recompile . success .

3 reflection

A little more , confirm .