c# - ASP.NET MVC 4，C# : how to Download File

Question

我之前已经将一个文件上传到我的数据库中，现在我想从我的数据库中下载该文件。

谁能告诉我怎么做？我是 C# 和 ASP.NET MVC 的新手。

Controller :

public ActionResult Details(string id = null)
{
        Assignment assignment = db.Assignments.Find(id);

        if (assignment == null)
        {
            return HttpNotFound();
        }

        return View(assignment);
}

型号:

public string AssignmentID { get; set; }
public Nullable<System.DateTime> SubmissionDate { get; set; }
public string Status { get; set; }
[Range(0,100, ErrorMessage="Only Value between 0-100 is accepted.")]
public Nullable<decimal> Mark { get; set; }
public string Comments { get; set; }
public byte[] FileLocation { get; set; }

查看:

<div class="display-label">
    <%: Html.DisplayNameFor(model => model.FileLocation) %>
</div>
<div class="display-field">
    <%: Html.DisplayFor(model => model.FileLocation) %>
</div>

Answer 1

因为你有一个 Stream 或 byte[] 或一个文件的路径，你可以使用 File() 方法来自 Controller 基类，并将此文件响应为 ActionResult，例如:

public ActionResult Details(string id = null)
{
     Assignment assignment = db.Assignments.Find(id);

     if (assignment == null)
     {
         return HttpNotFound();
     }

     return File(assigment.FileLocation, "content/type", "fileName.extension");
}

请记住获取正确的content-type 并添加具有正确扩展名的fileName。