When I build my application I get the following error
Error CS0579 Duplicate 'global::System.Runtime.Versioning.TargetFrameworkAttribute' attribute MyUIApp
D:\MyUIApp\obj\Debug\netcoreapp3.1\.NETCoreApp,Version=v3.1.AssemblyAttributes.cs 4 Active
The following code is autogenerated in the obj/Debug/netcoreapp3.1 folder
//
using System;
using System.Reflection;
[assembly: global::System.Runtime.Versioning.TargetFrameworkAttribute(".NETCoreApp,Version=v3.1", FrameworkDisplayName = "")]
I have a project file starting with
<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
<PropertyGroup>
<TargetFramework>netcoreapp3.1</TargetFramework>
<OutputType>Library</OutputType>
<SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\</SolutionDir>
<GenerateAssemblyInfo>false</GenerateAssemblyInfo>
<RestorePackages>true</RestorePackages>
<UseWindowsForms>true</UseWindowsForms>
</PropertyGroup>
<PropertyGroup>
I can work around the issue by commenting out the contents of the file, but not by deleting the file.
I was also getting this error in VS Code and the following fixed it.
I have a project/solution with three projects within in.
netstandard2.1
netstandard2.1
netcoreapp3.1
I added the following line to each of the *.csproj files within the <PropertyGroup> section:
<GenerateTargetFrameworkAttribute>false</GenerateTargetFrameworkAttribute>
Full example
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netstandard2.1</TargetFramework>
<GenerateTargetFrameworkAttribute>false</GenerateTargetFrameworkAttribute>
<GenerateAssemblyInfo>false</GenerateAssemblyInfo>
</PropertyGroup>
</Project>
After doing the above you might need to clean /bin and /obj folders for each project.
This article pointed me in the right direction though nothing online that I found mentioned the attribute above. I just guessed and it worked!
Add the following two lines to the <PropertyGroup>. This fixed it for me.
<PropertyGroup>
<GenerateAssemblyInfo>false</GenerateAssemblyInfo>
<GenerateTargetFrameworkAttribute>false</GenerateTargetFrameworkAttribute>
</PropertyGroup>
The problem was about my folder structure : the test project was in the main project folder. Passing each side by side in the same repo solved the problem
MyProject
src/MyProject.csproj
tests/MyTestProject.csproj
Taken from Github issue : https://github.com/dotnet/core/issues/4837
So i did encounter the same on a .NET 4.7 based solution, spent hours, only to find out a colleague of mine did include the obj and bin folders in the project!
excluding them fixed the issue and that error went away.
hope this save someone a couple of hours.
I fixed this by deleting the obj and bin folders in each project directory. I then cleaned the solution and rebuilt. The rebuild succeeded.
You just need to exclude the obj folder from the project/solution.
I was facing the same issue in my asp.net core 3.1 application right after I add the xUnit project to the solution. Ultimately, the main issue was because of that I selected the check box Place solution and project in the same directory as shown in the preceding image.
This should work in normal cases, and you will just consider this root directory as the Git repository (the .sln file and the .csproj will be in the same folder). But you will not be able to add a new project to this directory as you will get the error "Error CS0579 Duplicate 'global::System.Runtime.Versioning.TargetFrameworkAttribute'". So, to fix this error, we just have to follow the preceding steps.
Create a folder with the same name in the .sln file
Move all the project-related files to that directory
Open your .sln file with any code editor
Edit the Project references.
Make sure that your .sln file is in the root directory
This is how your project file references may look like now.
Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "WebApplication2", "WebApplication2\WebApplication2.csproj", "{027937D8-D0E6-45A4-8846-C2E28DA102E6}"
EndProject
Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "WebApplication2.Tests", "WebApplication2.Tests\WebApplication2.Tests.csproj", "{AD4C6C31-F617-4E76-985A-32B0E3104004}"
EndProject
That's it. Just reload your solution and happy coding!.
Try to delete obj folder from Project, delete it from SolutionExplorer instead of WindowExplorer.
I encountered that issue, what I did is I deleted the .NETCoreApp,Version=v3.1.AssemblyAttributes.cs and then I ran VSCode as an administrator.
I had this when my folder structure got messed up. I'm using Visual Studio 2019 and switched branches that has different folder structure. Some folders got added up in the file explorer and didn't get deleted even if I switched branches. All I did was to delete those folders that weren't part of my current branch and it worked.
I am having the same problem. As far as I can tell, the flag should prevent the auto-generation of assembly info. However, I can see this file in my obj directory:
.NETStandard,Version=v2.1.AssemblyAttributes.cs
It only contains the target version attribute. Maybe there is some other way of suppressing this attribute?
It seems like this might be a regression in .NET core 3.1.300. I was building with .NET core 3.1.200 and I didn't see this issue until I upgraded.
I experienced this on a build pipeline in Azure Devops. I was using a local agent to run the pipeline on (my own machine). It appears that there was code in the working directory that was causing this conflict, and by default, the agent doesn't clean the working directory before starting the pipeline process.
The fix was to delete the contents of the working directory on the agent. I did this by selecting the option to clean the working directory:
I had this kind of Errors in my Blazor Server project when I tried to add .NET Standard Class Library project in Visual Studio 2019.
Errors:
To fix this i tried following ways.
.csproj file Before
.csproj file After
In my case the culprit was my test project so I had to go to my test folder > obj > Debug/net6.0 > .NETCoreApp,Version=v6.0.AssemblyAttributes.cs
and then commented this line
[assembly:global::System.Runtime.Versioning.TargetFrameworkAttribute(".NETCoreApp,Version=v6.0", FrameworkDisplayName = "")]
This error can also happen if you accidentally copied an project file into another projects folder.
in my case (.NET 6.0);
I just exclude the Properties folder from the project/solution.
From the many different kind of answers, it's clear that there could be different reasons for the same issue. In my case the solution definition file was the cause. I decided to delete and create a clean solution file.
Delete the .sln file
Create a blank .sln file, in the root of your project/solution:
dotnet new sln
For every C# project file in your solution, add it with the following command, for example:
dotnet add MyApplication.csproj
and for example:
dotnet add CustomPackages/MyLibrary.csproj
Then to make sure all previous build artefacts are cleaned up
dotnet clean
Encountered this issue when working with AWS Lambda. Turns out I was switching branches, and some auto-generated folders did not get cleared after switching to new branch, and dotnet was picking them up for some reason. The easiest solution is to delete all local project folders, and check out clean version of the code again.
I commented out the offending attribute
// obj/Debug/netcoreapp3.1/.NETCoreApp,Version=v3.1.AssemblyAttributes.cs
using System;
using System.Reflection;
//[assembly: global::System.Runtime.Versioning.TargetFrameworkAttribute(".NETCoreApp,Version=v3.1", FrameworkDisplayName = "")]
DELETE [assembly: global::System.Runtime.Versioning.TargetFrameworkAttribute(".NETCoreApp,Version=v6.0", FrameworkDisplayName = "")]
I was able to solve this issue by getting a new clone of the project.
I have a custom Opencart shipping extension. It has upload/ and install.xml. When I upload extension.ocmod.zip through extension installer, it completes installation. But the extension is not visible under Extensions > Shipping.
I checked the code and none of the files from the extension is present under upload/admin/controller/extension/shipping.
I have refreshed modifications and cache from the dashboard.
Make sure that your file extension.ocmod.zip contains:
the upload folder and install.xml file directly
and there is not another subdirectory contains them
Without knowing the OC version you're using, my guess is that your path structure should be:
install.xml
upload/admin/view/extension/shipping/*
upload/admin/model/extension/shipping/*
upload/admin/controller/extension/shipping/*
upload/admin/language/en-gb/extension/shipping/*
upload/catalog/view/theme/default/extension/shipping/*
upload/catalog/model/extension/shipping/*
upload/catalog/controller/extension/shipping/*
upload/catalog/language/en-gb/extension/shipping/*
VS2017, SDK/WDK, C++ project
we have a c++ solution (driver) that is shared across developers via Team Foundation Services - visualstudio.com (now called azure devops?).
When I perform a get latest source code, and want to rebuild the solution I get two MSB3030 errors:
"Could not copy the file "C:\path of my colleague his file" because it was not found."
I found it strange that I saw on one of the two errors a path of my colleague his pc. He works on C:\ I'm working on E:\
Unloading the project, I saw he path being set here:
<ItemGroup>
<FilesToPackage Include="C:\path of my colleague\foo.xml" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
<PackageRelativeDirectory>
</PackageRelativeDirectory>
</FilesToPackage>
We cannot get this solution to build because of the MSB3030. First we have to clean the specific projects individually, rebuild it, then build another project etc.. a few steps to perform manually in the correct order , trial and error, drinking coffee, throwing bananas to the pc and praying that a monkey outputs the code correctly.
Has anyone seen somehting similar regarding MSB3030 errors?
On my pc I see the path of my colleague, but he doesn't see my path (strange!).
C:\Program Files (x86)\Windows
Kits\10\build\WindowsDriver.common.targets(1699,5): error MSB3030:
Could not copy the file 'C:...' because it was not found.
I've set the Any CPU to x64 because it doesn't make any sense for c++.
C++ Windows Driver MSB3030 could not copy the file '' because it was not found
The reason for this issue is that the path of the ItemGroup is an absolute path in the project file:
<ItemGroup>
<FilesToPackage Include="C:\path of my colleague\foo.xml" ...>
...
</FilesToPackage>
</ItemGroup>
Regardless of whether your colleague has added this file to source control, when you pull the code from the TFS server to your local and put the code in a different local folder, the absolute path will bring you a lot of trouble, you need to manually check the code on the TFS server for this file and you need to modify the absolute path of this file in your project. But this problem will reappear after your colleague updates after you submit your code. Because an absolute path cannot be assigned to two different paths C:\ and E:\.
To resolve this issue, you need to change the absolute path to a relative path in the source code. Generally, we prefer to add this file to the Solution/Project folder, then use the MSBuild Macros $(SolutionDir)/$(ProjectDir) to specify it.
Check Common macros for build commands and properties for some more details.
Hope this helps.
I'm trying to build opencv2 as a universal framework. I am systematically removing the files/folders that I do not need. But I am running into this issue where the include files are not found. See the image below:
The following image clearly shows that the file is indeed there.
One of the contractors working with us said he had put the include files into the same directory as the source files and rename them according to their file structure but using "." instead of "/" as shown below:
But that means that I must go through all of the files that include files and change the include statement to use "." instead of "/". REALLY?
Is this true? Or do we have a configuration set wrong?
You need to setup search paths for your target in Build Settings->Search Paths->Header search paths.
I have followed the instructions as per this article and have been working with Cocos2D without much issues. Recently, I tried including the Box2D headers to try some physics like so:
#import "Box2D.h"
This resulted in a lot of errors where the Box2D.h file could not include the rest of the header files:
../cocos2d-iphone-0.99.5/external/Box2d/Box2D/Box2D.h:34:0 ../cocos2d-iphone-0.99.5/external/Box2d/Box2D/Box2D.h:34:37: error: Box2D/Common/b2Settings.h: No such file or directory
That's the first error and the rest of the 23 are like that, but for the different headers in Box2D.h.
I have already added the projects/targets to the current project as per the instructions in the article, so my project currently looks like this:
Also, I have attempted to remedy this by selecting all .m files in my project and setting the file type to sourcecode.cpp.objcpp but do not think that this is the issue. I am certain that under the User Header Search Paths build setting, the folders where these headers are stored are added. If it weren't, Cocos2D wouldn't be able to compile either.
What am I doing wrong?
I don't know if this is immediately obvious to other programmers, but I fixed this by checking the Always Search User Paths setting in the target settings. Hope it helps someone else.
Another solition for me is removing blank characters from directory names. Forexample if your project folder such as
"user/prj 01"
change it to
"user/prj01".