c# - 尝试将图像保存到 wwwroot 时出现 DirectoryNotFoundException

Question

使用 this question我想出了这段代码来保存文件

[HttpPost]
public IActionResult Upload(string office, IFormFile file)
{
    if (file.Length > 0) {
        var filePath = Path.GetFullPath(Path.Combine(_environment.WebRootPath, 
            _configuration["SydneyFloorplanPath"]));

        using (var fileStream = new FileStream(filePath, FileMode.Create)) {
            file.CopyTo(fileStream);
        }
    }
    return RedirectToAction("Index", new{office = office});
}

但是在实例化 FileStream 时我遇到了一个非常烦人的问题:

An exception of type 'System.IO.DirectoryNotFoundException' occurred in System.Private.CoreLib.dll but was not handled in user code: 'Could not find a part of the path 'C:\images\Floorplan\sydney.pdf'.'

但这不是我需要的路径。 Images 文件夹位于我的项目中 wwwroot\images...

如果 WebRootPath 实际上没有给我一个可用的相对路径，那它还有什么意义呢？

注意 _environment 是一个注入(inject)的 IHostingEnvironment

我还注意到，如果我调用

var two = _environment.WebRootPath;

变量包含完整路径..."C:\\Users\\bassie\\source\\repos\\TFS\\DSSTools\\wwwroot"

但是在调用Path.Combine之后，我突然有了"C:\\images\\Floorplan\\sydney.pdf" ...为什么？

编辑:

_environment 是一个IHostingEnvironment，例如:

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;

namespace AspNetCorePathMapping
{
    public class HomeController : Controller
    {
        private readonly IHostingEnvironment _hostingEnvironment;

        public HomeController(IHostingEnvironment hostingEnvironment)
        {
            _hostingEnvironment = hostingEnvironment;
        }

        public ActionResult Index()
        {
            string webRootPath = _hostingEnvironment.WebRootPath;
            string contentRootPath = _hostingEnvironment.ContentRootPath;

            return Content(webRootPath + "\n" + contentRootPath);
        }
    }
}

Answer 1

我设法让它工作

[HttpPost]
public IActionResult Upload(string office, IFormFile file)
{
    var webRootPath  = _environment.WebRootPath;
    var floorPlanPath =  _configuration["SydneyFloorplanPath"];

    if (file.Length > 0) {
        var filePath1 = Path.Combine(floorPlanPath,webRootPath.ReplaceFirst("/", ""));

        using (var fileStream = new FileStream(filePath1, FileMode.Create)) {
            file.CopyTo(fileStream);
        }
    }
    return RedirectToAction("Index", new{office = office});
}

ReplaceFirst 是一个简单的 StringExtension

public static string ReplaceFirst(this string text, string search, string replace)
{
    int pos = text.IndexOf(search);
    if (pos < 0)
    {
        return text;
    }
    return $"{text.Substring(0, pos)}{replace}{text.Substring(pos + search.Length)}";
}

看来 webRootPath 中的前导 / 破坏了我的 Path.Combine 调用