ASP.NET Core 找不到 npm指令异常

1.错误再现

利用VS2019预览版创建ASP.NET Core 的单页面Web程序

创建后直接运行，出现如下错误

 Ensure that 'npm' is installed and can be found in one of the PATH directories.

2.相关资料

找到以下资料

https://github.com/aspnet/AspNetCore/issues/5263

https://github.com/aspnet/AspNetCore.Docs/blob/master/aspnetcore/host-and-deploy/aspnet-core-module/samples_snapshot/2.x/CurrentDirectoryHelpers.cs

3.解决方案

添加类CurrentDirectoryHelpers，代码如下

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace WebApplication6
{
    public class CurrentDirectoryHelpers
    {
        internal const string AspNetCoreModuleDll = "aspnetcorev2_inprocess.dll";

        [System.Runtime.InteropServices.DllImport("kernel32.dll")]
        private static extern IntPtr GetModuleHandle(string lpModuleName);

        [System.Runtime.InteropServices.DllImport(AspNetCoreModuleDll)]
        private static extern int http_get_application_properties(ref IISConfigurationData iiConfigData);

        [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
        private struct IISConfigurationData
        {
            public IntPtr pNativeApplication;
            [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.BStr)]
            public string pwzFullApplicationPath;
            [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.BStr)]
            public string pwzVirtualApplicationPath;
            public bool fWindowsAuthEnabled;
            public bool fBasicAuthEnabled;
            public bool fAnonymousAuthEnable;
        }

        public static void SetCurrentDirectory()
        {
            try
            {
                // Check if physical path was provided by ANCM
                var sitePhysicalPath = Environment.GetEnvironmentVariable("ASPNETCORE_IIS_PHYSICAL_PATH");
                if (string.IsNullOrEmpty(sitePhysicalPath))
                {
                    // Skip if not running ANCM InProcess
                    if (GetModuleHandle(AspNetCoreModuleDll) == IntPtr.Zero)
                    {
                        return;
                    }

                    IISConfigurationData configurationData = default(IISConfigurationData);
                    if (http_get_application_properties(ref configurationData) != 0)
                    {
                        return;
                    }

                    sitePhysicalPath = configurationData.pwzFullApplicationPath;
                }

                Environment.CurrentDirectory = sitePhysicalPath;
            }
            catch
            {
                // ignore
            }
        }
    }
}

在Main方法中调用

运行，发现神奇般的好啦！！！