对于.NET核心项目，在NuGet包管理器控制台中运行dotnet restore或dotnet build命令(会自动运行恢复)

您可以从运行控制台

> NuGet包管理器>包管理器控制台

当将带有nuget包的项目从Vx20XX升级到VS2015时，您可能会遇到nuget包的问题。

错误信息示例: 该项目引用了这台计算机上缺少的NuGet包。启用NuGet包还原来下载它们。

更新2016-02-06:我有一个链接的信息，但它不再工作了。我怀疑最近的路径已经解决了这个问题??

我解决了我的问题，写了一个小程序，做msbuild集成包恢复vs.自动包恢复

您可以在这里下载该工具的可执行文件。

请让我知道结果!

代码参考:

<Window x:Class="FixNuGetProblemsInVs2015.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:FixNuGetProblemsInVs2015"
        mc:Ignorable="d"
        Title="Fix NuGet Packages problems in Visual Studio 2015 (By Eric Ouellet)" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"></ColumnDefinition>
            <ColumnDefinition Width="10"></ColumnDefinition>
            <ColumnDefinition></ColumnDefinition>
        </Grid.ColumnDefinitions>

        <TextBlock Grid.Row="0" Grid.Column="0">Root directory of projects</TextBlock>
        <Grid Grid.Row="0" Grid.Column="2">
            <Grid.ColumnDefinitions>
                <ColumnDefinition></ColumnDefinition>
                <ColumnDefinition Width="Auto"></ColumnDefinition>
            </Grid.ColumnDefinitions>

            <TextBox Grid.Column="0" Name="DirProjects"></TextBox>
            <Button Grid.Column="1" VerticalAlignment="Bottom" Name="BrowseDirProjects" Click="BrowseDirProjectsOnClick">Browse...</Button>
        </Grid>

        <!--<TextBlock Grid.Row="1" Grid.Column="0">Directory of NuGet Packages</TextBlock>
        <Grid Grid.Row="1" Grid.Column="2">
            <Grid.ColumnDefinitions>
                <ColumnDefinition></ColumnDefinition>
                <ColumnDefinition Width="Auto"></ColumnDefinition>
            </Grid.ColumnDefinitions>

            <TextBox Grid.Column="0" Name="DirPackages"></TextBox>
            <Button Grid.Column="1"  Name="BrowseDirPackages" Click="BrowseDirPackagesOnClick">Browse...</Button>
        </Grid>-->

        <TextBox Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="3" Name="TxtLog" IsReadOnly="True"></TextBox>

        <Button Grid.Row="3" Grid.Column="0" Click="ButtonRevertOnClick">Revert back</Button>
        <Button Grid.Row="3" Grid.Column="2" Click="ButtonFixOnClick">Fix</Button>
    </Grid>
</Window>


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Forms;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Xml;
using System.Xml.Linq;
using Application = System.Windows.Application;
using MessageBox = System.Windows.MessageBox;

/// <summary>
/// Applying recommanded modifications in section : "MSBuild-Integrated package restore vs. Automatic Package Restore"
/// of : http://docs.nuget.org/Consume/Package-Restore/Migrating-to-Automatic-Package-Restore
/// </summary>

namespace FixNuGetProblemsInVs2015
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            DirProjects.Text = @"c:\prj";
            // DirPackages.Text = @"C:\PRJ\NuGetPackages";
        }

        private void BrowseDirProjectsOnClick(object sender, RoutedEventArgs e)
        {
            FolderBrowserDialog dlg = new FolderBrowserDialog();
            dlg.SelectedPath = DirProjects.Text;
            if (dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                DirProjects.Text = dlg.SelectedPath;
            }
        }

        //private void BrowseDirPackagesOnClick(object sender, RoutedEventArgs e)
        //{
        //  FolderBrowserDialog dlg = new FolderBrowserDialog();
        //  dlg.SelectedPath = DirPackages.Text;
        //  if (dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        //  {
        //      DirPackages.Text = dlg.SelectedPath;
        //  }
        //}

        // private string _dirPackages;

        private void ButtonFixOnClick(object sender, RoutedEventArgs e)
        {
            DoJob(false);
        }

        private void ButtonRevertOnClick(object sender, RoutedEventArgs e)
        {
            DoJob(true);
        }

        private void DoJob(bool revert = false)
        {
            TxtLog.Text = "";

            string dirProjects = DirProjects.Text;
            // _dirPackages = DirPackages.Text;

            if (!Directory.Exists(dirProjects))
            {
                MessageBox.Show("Projects directory does not exists: " + dirProjects);
                return;
            }

            //if (!Directory.Exists(_dirPackages))
            //{
            //  MessageBox.Show("Packages directory does not exists: " + _dirPackages);
            //  return;
            //}

            RecurseFolder(dirProjects, revert);
        }

        private void RecurseFolder(string dirProjects, bool revert = false)
        {
            if (revert)
            {
                Revert(dirProjects);
            }
            else
            {
                FixFolder(dirProjects);
            }

            foreach (string subfolder in Directory.EnumerateDirectories(dirProjects))
            {
                RecurseFolder(subfolder, revert);
            }
        }

        private const string BackupSuffix = ".fix_nuget_backup";

        private void Revert(string dirProject)
        {
            foreach (string filename in Directory.EnumerateFiles(dirProject))
            {
                if (filename.ToLower().EndsWith(BackupSuffix))
                {
                    string original = filename.Substring(0, filename.Length - BackupSuffix.Length);
                    if (File.Exists(original))
                    {
                        File.Delete(original);                                          
                    }
                    File.Move(filename, original);
                    Log("File reverted: " + filename + " ==> " + original);
                }
            }
        }

        private void FixFolder(string dirProject)
        {
            BackupFile(System.IO.Path.Combine(dirProject, "nuget.targets"));
            BackupFile(System.IO.Path.Combine(dirProject, "nuget.exe"));

            foreach (string filename in Directory.EnumerateFiles(dirProject))
            {
                if (filename.ToLower().EndsWith(".csproj"))
                {
                    FromProjectFileRemoveNugetTargets(filename);
                }
            }
        }

        private void BackupFile(string path)
        {
            if (File.Exists(path))
            {
                string backup = path + BackupSuffix;
                if (!File.Exists(backup))
                {
                    File.Move(path, backup);
                    Log("File backup: " + backup);
                }
                else
                {
                    Log("Project has already a backup: " + backup);
                }
            }
        }

        private void FromProjectFileRemoveNugetTargets(string prjFilename)
        {
            XDocument xml = XDocument.Load(prjFilename);

            List<XElement> elementsToRemove = new List<XElement>();

            foreach (XElement element in xml.Descendants())
            {
                if (element.Name.LocalName == "Import")
                {
                    var att = element.Attribute("Project");
                    if (att != null)
                    {
                        if (att.Value.Contains("NuGet.targets"))
                        {
                            elementsToRemove.Add(element);
                        }
                    }
                }

                if (element.Name.LocalName == "Target")
                {
                    var att = element.Attribute("Name");
                    if (att != null && att.Value == "EnsureNuGetPackageBuildImports")
                    {
                        elementsToRemove.Add(element);
                    }
                }
            }

            if (elementsToRemove.Count > 0)
            {
                elementsToRemove.ForEach(element => element.Remove());
                BackupFile(prjFilename);
                xml.Save(prjFilename);
                Log("Project updated: " + prjFilename);
            }
        }

        private void Log(string msg)
        {
            TxtLog.Text += msg + "\r\n";
        }

    }
}

微软已经在VS2015中放弃了对“启用NuGet包恢复”的支持，你需要做一些手动更改来迁移旧的解决方案或将该功能添加到新的解决方案中。这个新特性在NuGet包还原中有很好的描述。

这里还有一个针对现有项目的迁移指南(如前所述):NuGet迁移指南

当升级:

不要删除。nuget目录。 删除nuget.exe和nuget.exe。目标文件。 保留nuget.config。 手动清除每个项目文件中对NuGet目标的任何引用。上面提到的Powershell脚本似乎弊大于利。

创建新项目时:

In your Visual Studio 2015 solution, create a Solution Directory called .nuget. Create an actual directory of the solution directory (where the .sln file lives) and call it .nuget (note that the solution directory is not the same as the actual file system directory even though they have the same name). Create a file in the .nuget directory called nuget.config. Add the 'nuget.config' to the solution directory created in step #2. Place the following text in the nuget.config file: <?xml version="1.0" encoding="utf-8"?> <configuration> <config> <add key="repositorypath" value="$\..\..\..\..\Packages" /> </config> <solution> <add key="disableSourceControlIntegration" value="true" /> </solution> </configuration>

这个配置文件将允许您将所有包合并到一个地方，这样您就不会在文件系统中有相同包的20个不同副本。相对路径将根据您的解决方案目录体系结构而改变，但它应该指向所有解决方案的公共目录。

在执行步骤5后，需要重新启动visual studio。除非你这样做，否则Nuget不会发现这些变化。

最后，您可能必须使用“Nuget包管理器的解决方案”卸载，然后重新安装包。我不知道这是否是我运行的Powershell脚本的副作用，或者只是踢NuGet回到齿轮的方法。当我完成了所有这些步骤后，当我从TFVC签出项目时，我复杂的构建体系结构完美地运行了新的包。

关闭VS.删除packages文件夹下的所有内容。重新打开解决方案。右键单击项目，选择“Manage nuget packages…”。您将看到一个黄色条出现在“Nuget包管理器”窗口的顶部，要求您恢复包。这对我来说很有效。

更简单的是，在解决方案中添加一个. Nuget文件夹，然后就会出现“还原Nuget包”(不确定是否需要Nuget .exe才能正常工作)。

针对。net Core 3.1的VS 2019版本16.4.4解决方案

在尝试了这里提出的几乎所有解决方案之后，我关闭了VS。 当我重新打开它时，几秒钟后一切都恢复正常了……