Question

我正在尝试进行简单的文件下载，但是会导致FileNotFoundException。

控制器中的代码：

public FileResult DownloadFile()
{
    var fileName = "1.pdf";
    var filePath = env.WebRootPath + "\\" + fileName;
    var fileExists = System.IO.File.Exists(filePath);
    return File(filePath, "application/pdf", fileName);
}

（调试变量fileExists显示它已设置为true。）

视图中的代码：

@Html.ActionLink("Download", "DownloadFile")

来自日志的消息：

2017-03-12 09:28:45 [INF] Executing action method "Team.Controllers.ModulesExController.DownloadFile (Team)" with arguments (null) - ModelState is Valid
2017-03-12 09:28:45 [DBG] Executed action method "Team.Controllers.ModulesExController.DownloadFile (Team)", returned result "Microsoft.AspNetCore.Mvc.VirtualFileResult".
2017-03-12 09:28:45 [INF] Executing FileResult, sending file as "1.pdf"
2017-03-12 09:28:45 [INF] Executed action "Team.Controllers.ModulesExController.DownloadFile (Team)" in 0.8238ms
2017-03-12 09:28:45 [DBG] System.IO.FileNotFoundException occurred, checking if Entity Framework recorded this exception as resulting from a failed database operation.
2017-03-12 09:28:45 [DBG] Entity Framework did not record any exceptions due to failed database operations. This means the current exception is not a failed Entity Framework database operation, or the current exception occurred from a DbContext that was not obtained from request services.
2017-03-12 09:28:45 [ERR] An unhandled exception has occurred while executing the request
System.IO.FileNotFoundException: Could not find file: D:\Projekti\Team\src\Team\wwwroot\1.pdf

如果我将链接粘贴到浏览器的错误消息中，我可以打开该文件。

Answer 1

Controller.File()期待虚拟路径，而不是绝对路径。

参见 https://docs.microsoft.com/en-us/aspnet/core/api/microsoft.aspnetcore.mvc.controllerbase#Microsoft_AspNetCore_Mvc_ControllerBase_File_System_String_System_String_System_String_

如果您想使用绝对路径，请传入一个流：

public FileResult DownloadFile()
{
    var fileName = "1.pdf";
    var filePath = env.WebRootPath + "\\" + fileName;
    var fileExists = System.IO.File.Exists(filePath);
    var fs = System.IO.File.OpenRead(filePath);
    return File(fs, "application/pdf", fileName);
}

Answer 2

在ASP.NET Core 2.0中，如果您有文件路径，则可以使用PhysicalFile作为返回类型。

    public FileResult DownloadFile() {
        var fileName = "1.pdf";
        var filePath = env.WebRootPath + "\\" + fileName;
        var fileExists = System.IO.File.Exists(filePath);
        return PhysicalFile(filePath, "application/pdf", fileName);
    }

asp net core - 文件下载结果是FileNotFoundException

2 个答案: