C# 旧模式（packages.config）读取全部依赖关系，同时获得顶级依赖代码

代码：

using System;
using System.Collections.Generic;
using System.Linq;
using NuGet.ProjectModel;
using NuGet.PackageManagement;
using NuGet.Common;
using NuGet.Packaging.Core;
using NuGet.Protocol;
using NuGet.Protocol.Core.Types;
using NuGet.Versioning;
using static NuGet.Frameworks.FrameworkConstants;
using static NuGet.Protocol.Core.Types.Repository;
using System.Threading;
using System.Threading.Tasks;
using NuGet.Test.Utility;
using Xunit;
//using Test_Tools;
namespace Test_Tools
{

    class Program 
    {
        static public void Main(string[] args)
        {
            PackageGraphAnalysisUtilities_GetDependencyInfoForPackageIdentitiesAsync_SucceedsAsync();
            // Console.WriteLine();
            //Top_level();
            Console.ReadKey();  
            
        }

        public static void Top_level()
        {
            var packageIdentityA100 = new PackageIdentity("a", NuGetVersion.Parse("2.2.0"));
            var packageIdentityB100 = new PackageIdentity("b", NuGetVersion.Parse("13.0.1"));
            var packageDependencyInfos = new List<PackageDependencyInfo>();
            //制造关于A的依赖图
            var packageDependencyInfoA = new PackageDependencyInfo(packageIdentityA100,
                new PackageDependency[] {
                    new PackageDependency(packageIdentityB100.Id, VersionRange.Parse("[9.0.1,)")),
                });
            var packageDependencyInfoB = new PackageDependencyInfo(packageIdentityB100, Enumerable.Empty<PackageDependency>());

            //增加所有的依赖关系图
            packageDependencyInfos.Add(packageDependencyInfoA);
            packageDependencyInfos.Add(packageDependencyInfoB);
            // Act————》》获取依赖图___>>>用的是package的获取整个依赖图
            var packageWithDependants = PackageGraphAnalysisUtilities.GetPackagesWithDependants(packageDependencyInfos);
            foreach(var package in packageWithDependants)
            {
                Console.WriteLine(package.Identity.Id);
                Console.WriteLine(package.IsTopLevelPackage);
            }
        }
        public static async Task PackageGraphAnalysisUtilities_GetDependencyInfoForPackageIdentitiesAsync_SucceedsAsync()
        {
            using (var pathContext = new SimpleTestPathContext())
            {
                string Path_Resorece =@"D:\VS2017\WorkSpace\Nufix\Test_Tools\Test_Tools\WorkPlace\PackageResource";
                //直接获取nupkg包这样的环境
                var sourceReposistory = Factory.GetCoreV3(Path_Resorece);
                var installedList = new PackageIdentity[]
                {
                    new PackageIdentity("LibraryA", NuGetVersion.Parse("1.0.0")),
                    //new PackageIdentity("Newtonsoft.Json", NuGetVersion.Parse("13.0.1")),
                    new PackageIdentity("Newtonsoft.Json", NuGetVersion.Parse("12.0.1")),
                };
                //工作的流程——》把所有的依赖项都放到一起，制作出来一个环境，然后根据这些环境构建之间的依赖关系
                // Act
                var packageDependencyInfos = await PackageGraphAnalysisUtilities.GetDependencyInfoForPackageIdentitiesAsync(
                    packageIdentities: installedList,
                    nuGetFramework: CommonFrameworks.NetStandard20,//甚至可以判断出来平台的兼容性！！！！！！！
                    dependencyInfoResource: await sourceReposistory.GetResourceAsync<DependencyInfoResource>(),//从Resourse中返回资源
                    sourceCacheContext: new SourceCacheContext(),
                    includeUnresolved: true,
                    logger: NullLogger.Instance,
                    cancellationToken: CancellationToken.None
                    );
                // Assert
                Console.WriteLine(packageDependencyInfos.Count());
                var Tops_List = new List<PackageDependencyInfo>();
                foreach (var package in packageDependencyInfos)
                {
                    Console.WriteLine(package.Id);
                    Console.WriteLine(package.Dependencies.Count());
                    var packageIdentity = new PackageIdentity(package.Id, package.Version);
                    var packageDependencyInfo = new PackageDependencyInfo(packageIdentity, Enumerable.Empty<PackageDependency>());
                    if (package.Dependencies.Count() > 0)
                    {
                        var PackageDependency_ = package.Dependencies;
                        packageDependencyInfo = new PackageDependencyInfo(packageIdentity, PackageDependency_);

                    }
                    Tops_List.Add(packageDependencyInfo);
                }
                Console.WriteLine("RTRTRTRTR");
                //通过依赖图构建全局关系
                var packageWithDependants = PackageGraphAnalysisUtilities.GetPackagesWithDependants(Tops_List);

                foreach (var package in packageWithDependants)
                {
                    Console.WriteLine(package.Identity.Id);
                    Console.WriteLine(package.IsTopLevelPackage);
                }
            }

        }

    }
}