如何在ASP.Net Core中为Server.MapPath获取绝对路径

18

1 年前

如何获得ASP网核替代方式的绝对路径 Server.MapPath

我曾尝试使用 IHostingEnvironment 但它没有给出正确的结果 .

IHostingEnvironment env = new HostingEnvironment();var str1 = env.ContentRootPath; // Nullvar str2 = env.WebRootPath; // Null, both doesn't give any result

我在wwwroot文件夹中有一个图像文件（Sample.PNG）我需要获取这个绝对路径 .

• c#asp.netasp.net-coreasp.net-core-mvc

3回答

• 
  1
  

  8 个月前

  将 IHostingEnvironment 作为依赖项注入依赖类 . 该框架将为您填充它

  public class HomeController : Controller {    private IHostingEnvironment _hostingEnvironment;    public HomeController(IHostingEnvironment environment) {        _hostingEnvironment = environment;    }    [HttpGet]    public IActionResult Get() {        var path = Path.Combine(_hostingEnvironment.WebRootPath, "Sample.PNG");        return View();    }}

  您可以更进一步，创建自己的路径提供程序

  public interface IPathProvider {    string MapPath(string path);}public class PathProvider : IPathProvider {    private IHostingEnvironment _hostingEnvironment;    public PathProvider(IHostingEnvironment environment) {        _hostingEnvironment = environment;    }    public string MapPath(string path) {        var filePath = Path.Combine(_hostingEnvironment.WebRootPath, path);        return filePath;    }}

  并将 IPathProvider 注入依赖类 .

  public class HomeController : Controller {    private IPathProvider pathProvider;    public HomeController(IPathProvider pathProvider) {        this.pathProvider = pathProvider;    }    [HttpGet]    public IActionResult Get() {        var path = pathProvider.MapPath("Sample.PNG");        return View();    }}

  确保使用容器注册服务

  services.AddSingleton<IPathProvider, PathProvider>();

• 
  52
  

  8 个月前

  更好的解决方案是使用 IFileProvider.GetFileInfo() 方法 .

  public IActionResult ResizeCat([FromServices] IFileProvider fileProvider)    {        // get absolute path (equivalent to MapPath)        string absolutePath = fileProvider.GetFileInfo("/assets/images/cat.jpg").PhysicalPath;          ...     }

  你必须注册 IFileProvider like this to be able to access it through DI：

  // This method gets called by the runtime. Use this method to add services to the container.    public void ConfigureServices(IServiceCollection services)    {        // Add framework services.        services.AddMvc();        var physicalProvider = _hostingEnvironment.ContentRootFileProvider;        var embeddedProvider = new EmbeddedFileProvider(Assembly.GetEntryAssembly());        var compositeProvider = new CompositeFileProvider(physicalProvider, embeddedProvider);        // choose one provider to use for the app and register it        //services.AddSingleton<IFileProvider>(physicalProvider);        //services.AddSingleton<IFileProvider>(embeddedProvider);        services.AddSingleton<IFileProvider>(compositeProvider);    }

  正如您所看到的那样，逻辑（文件来自哪里）可能变得非常复杂，但如果更改，您的代码将不会中断 .

  如果您有一些特殊逻辑，可以使用 new PhysicalFileProvider(root) 创建自定义 IFileProvider . 我有一种情况，我想在中间件中加载图像，并调整大小或裁剪它 . 但它是一个Angular项目，因此部署的应用程序的路径不同 . 我编写的中间件从 startup.cs 获取 IFileProvider 然后我可以使用 GetFileInfo() ，就像我过去使用 MapPath 一样 .

• 
  0
  

  8 个月前

  *** Hack *** 不推荐，但是你可以通过 var abs = Path.GetFullPath("~/Content/Images/Sample.PNG").Replace("~\\",""); 获得相对路径的绝对路径

  更喜欢上面的DI /服务方法，但如果您处于非DI情况（例如，用 Activator 实例化的类），这将起作用 .