NU1100:Unable to resolve 'Microsoft.NET.Sdk.Functions (>= 3.0.3)' for '.NETCoreApp,Version=v3.1'

Question

When attempting to work with Azure functions, I get this error. I am just trying to run the HttpExample I get the exact same error from the command as I do in Visual Studio Code. This is the code. I am a beginner at this so any help would be appricated.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <AzureFunctionsVersion>v3</AzureFunctionsVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="3.0.3" />
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

Answer 1

Yes, I agree with Cindy's answer. Having no entries or incorrect package source entries in packageSources xml node in Nuget.Config can cause the error.

I have just encountered the same error when creating an Azure Function version 4.0.1 with .Net 6 released just a few days ago in Visual Studio Code. I do not have Visual Studio 2022 installed. I have .Net 6 SDK installed and use it with Visual Studio Code. You would think that the NuGet utility installed with.Net 6 SDK should have configured <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" /> in your user level or global level NuGet settings by default. But it did not.

I run do.net nuget add source https://api.nuget.org/v3/index.json -n nuget.org command in a DOS Command Prompt or a PowerShell session to add the nuget.org as a packageSource in my user level setting nuget.config file. That solved the **NU1100 Unable to resolve ** error.

On another note, I would say Visual Studio 2022 or its previous versions will configure nuget.org as the default package source for NuGet because I did not have to do that manually when I used Visual Studio 2017 before to download or restore NuGet packages.

Answer 2

The format of your.csproj file is actually no problem. Your code of.csproj works fine on my side.

By the way, version 3.0.3 of Microsoft.NET.Sdk.Functions is compatible with.Net Core 3.1. I think the problem is with your package management tool. If you use nuget, please check its configuration.

This is my Nuget.Config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
  </packageSources>
</configuration>

Or you can try to reinstall your nuget management tool.