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

 

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！！！