检查我的解决方案

public string SaveFile(HttpPostedFileBase uploadfile, string saveInDirectory="/", List<string> acceptedExtention =null)
{
    acceptedExtention = acceptedExtention ?? new List<String>() {".png", ".Jpeg"};//optional arguments

    var extension = Path.GetExtension(uploadfile.FileName).ToLower();

    if (!acceptedExtention.Contains(extension))
    {
        throw new UserFriendlyException("Unsupported File type");
    }
    var tempPath = GenerateDocumentPath(uploadfile.FileName, saveInDirectory);
    FileHelper.DeleteIfExists(tempPath);
    uploadfile.SaveAs(tempPath);

    var fileName = Path.GetFileName(tempPath);
    return fileName;
}

private string GenerateDocumentPath(string fileName, string saveInDirectory)
{
    System.IO.Directory.CreateDirectory(Server.MapPath($"~/{saveInDirectory}"));
    return Path.Combine(Server.MapPath($"~/{saveInDirectory}"), Path.GetFileNameWithoutExtension(fileName) +"_"+ DateTime.Now.Ticks + Path.GetExtension(fileName));
}

在基本控制器中添加这些函数，以便可以在所有控制器中使用它们

检查如何使用它

SaveFile(view.PassportPicture,acceptedExtention:new List<String>() { ".png", ".Jpeg"},saveInDirectory: "content/img/PassportPicture");

下面是一个完整的例子

[HttpPost]
public async Task<JsonResult> CreateUserThenGenerateToken(CreateUserViewModel view)
{// CreateUserViewModel contain two properties of type HttpPostedFileBase  
    string passportPicture = null, profilePicture = null;
    if (view.PassportPicture != null)
    {
        passportPicture = SaveFile(view.PassportPicture,acceptedExtention:new List<String>() { ".png", ".Jpeg"},saveInDirectory: "content/img/PassportPicture");
    }
    if (view.ProfilePicture != null)
    {
        profilePicture = SaveFile(yourHttpPostedFileBase, acceptedExtention: new List<String>() { ".png", ".Jpeg" }, saveInDirectory: "content/img/ProfilePicture");
    }
    var input = view.MapTo<CreateUserInput>();
    input.PassportPicture = passportPicture;
    input.ProfilePicture = profilePicture;


    var getUserOutput = await _userAppService.CreateUserThenGenerateToken(input);
    return new AbpJsonResult(getUserOutput);
    //return Json(new AjaxResponse() { Result = getUserOutput, Success = true });

}

保存多个文件的简单方法

cshtml

@using (Html.BeginForm("Index","Home",FormMethod.Post,new { enctype = "multipart/form-data" }))
{
    <label for="file">Upload Files:</label>
    <input type="file" multiple name="files" id="files" /><br><br>
    <input type="submit" value="Upload Files" />
    <br><br>
    @ViewBag.Message
}

控制器

[HttpPost]
        public ActionResult Index(HttpPostedFileBase[] files)
        {
            foreach (HttpPostedFileBase file in files)
            {
                if (file != null && file.ContentLength > 0)
                    try
                    {
                        string path = Path.Combine(Server.MapPath("~/Files"), Path.GetFileName(file.FileName));
                        file.SaveAs(path);
                        ViewBag.Message = "File uploaded successfully";
                    }
                    catch (Exception ex)
                    {
                        ViewBag.Message = "ERROR:" + ex.Message.ToString();
                    }

                else
                {
                    ViewBag.Message = "You have not specified a file.";
                }
            }
            return View();
        }

在视图中：

<form action="Categories/Upload" enctype="multipart/form-data" method="post">
    <input type="file" name="Image">
    <input type="submit" value="Save">
</form>

而控制器中的以下代码：

public ActionResult Upload()
{
    foreach (string file in Request.Files)
    {
       var hpf = this.Request.Files[file];
       if (hpf.ContentLength == 0)
       {
            continue;
       }

       string savedFileName = Path.Combine(
                AppDomain.CurrentDomain.BaseDirectory, "PutYourUploadDirectoryHere");
                savedFileName = Path.Combine(savedFileName, Path.GetFileName(hpf.FileName));

        hpf.SaveAs(savedFileName);
    }

    ...
}

要传输到字节[]（例如，用于保存到DB）：

using (MemoryStream ms = new MemoryStream()) {
    file.InputStream.CopyTo(ms);
    byte[] array = ms.GetBuffer();
}

若要将输入流直接传输到数据库中，而不将其存储在内存中，您可以使用从此处获取的此类，并稍作更改：

public class VarbinaryStream : Stream {
private SqlConnection _Connection;

private string _TableName;
private string _BinaryColumn;
private string _KeyColumn;
private int _KeyValue;

private long _Offset;

private SqlDataReader _SQLReader;
private long _SQLReadPosition;

private bool _AllowedToRead = false;

public VarbinaryStream(
    string ConnectionString,
    string TableName,
    string BinaryColumn,
    string KeyColumn,
    int KeyValue,
    bool AllowRead = false)
{
  // create own connection with the connection string.
  _Connection = new SqlConnection(ConnectionString);

  _TableName = TableName;
  _BinaryColumn = BinaryColumn;
  _KeyColumn = KeyColumn;
  _KeyValue = KeyValue;


  // only query the database for a result if we are going to be reading, otherwise skip.
  _AllowedToRead = AllowRead;
  if (_AllowedToRead == true)
  {
    try
    {
      if (_Connection.State != ConnectionState.Open)
        _Connection.Open();

      SqlCommand cmd = new SqlCommand(
                      @"SELECT TOP 1 [" + _BinaryColumn + @"]
                            FROM [dbo].[" + _TableName + @"]
                            WHERE [" + _KeyColumn + "] = @id",
                  _Connection);

      cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));

      _SQLReader = cmd.ExecuteReader(
          CommandBehavior.SequentialAccess |
          CommandBehavior.SingleResult |
          CommandBehavior.SingleRow |
          CommandBehavior.CloseConnection);

      _SQLReader.Read();
    }
    catch (Exception e)
    {
      // log errors here
    }
  }
}

// this method will be called as part of the Stream ímplementation when we try to write to our VarbinaryStream class.
public override void Write(byte[] buffer, int index, int count)
{
  try
  {
    if (_Connection.State != ConnectionState.Open)
      _Connection.Open();

    if (_Offset == 0)
    {
      // for the first write we just send the bytes to the Column
      SqlCommand cmd = new SqlCommand(
                                  @"UPDATE [dbo].[" + _TableName + @"]
                                            SET [" + _BinaryColumn + @"] = @firstchunk 
                                        WHERE [" + _KeyColumn + "] = @id",
                              _Connection);

      cmd.Parameters.Add(new SqlParameter("@firstchunk", buffer));
      cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));

      cmd.ExecuteNonQuery();

      _Offset = count;
    }
    else
    {
      // for all updates after the first one we use the TSQL command .WRITE() to append the data in the database
      SqlCommand cmd = new SqlCommand(
                              @"UPDATE [dbo].[" + _TableName + @"]
                                        SET [" + _BinaryColumn + @"].WRITE(@chunk, NULL, @length)
                                    WHERE [" + _KeyColumn + "] = @id",
                           _Connection);

      cmd.Parameters.Add(new SqlParameter("@chunk", buffer));
      cmd.Parameters.Add(new SqlParameter("@length", count));
      cmd.Parameters.Add(new SqlParameter("@id", _KeyValue));

      cmd.ExecuteNonQuery();

      _Offset += count;
    }
  }
  catch (Exception e)
  {
    // log errors here
  }
}

// this method will be called as part of the Stream ímplementation when we try to read from our VarbinaryStream class.
public override int Read(byte[] buffer, int offset, int count)
{
  try
  {
    long bytesRead = _SQLReader.GetBytes(0, _SQLReadPosition, buffer, offset, count);
    _SQLReadPosition += bytesRead;
    return (int)bytesRead;
  }
  catch (Exception e)
  {
    // log errors here
  }
  return -1;
}
public override bool CanRead
{
  get { return _AllowedToRead; }
}

protected override void Dispose(bool disposing)
{
  if (_Connection != null)
  {
    if (_Connection.State != ConnectionState.Closed)
      try { _Connection.Close();           }
      catch { }
    _Connection.Dispose();
  }
  base.Dispose(disposing);
}

#region unimplemented methods
public override bool CanSeek
{
  get { return false; }
}

public override bool CanWrite
{
  get { return true; }
}

public override void Flush()
{
  throw new NotImplementedException();
}

public override long Length
{
  get { throw new NotImplementedException(); }
}

public override long Position
{
  get
  {
    throw new NotImplementedException();
  }
  set
  {
    throw new NotImplementedException();
  }
}
public override long Seek(long offset, SeekOrigin origin)
{
  throw new NotImplementedException();
}

public override void SetLength(long value)
{
  throw new NotImplementedException();
}
#endregion unimplemented methods  }

以及用法：

  using (var filestream = new VarbinaryStream(
                            "Connection_String",
                            "Table_Name",
                            "Varbinary_Column_name",
                            "Key_Column_Name",
                            keyValueId,
                            true))
  {
    postedFile.InputStream.CopyTo(filestream);
  }

在控制器中

 if (MyModal.ImageFile != null)
                    {
                        MyModal.ImageURL = string.Format("{0}.{1}", Guid.NewGuid().ToString(), MyModal.ImageFile.FileName.Split('.').LastOrDefault());
                        if (MyModal.ImageFile != null)
                        {
                            var path = Path.Combine(Server.MapPath("~/Content/uploads/"), MyModal.ImageURL);
                            MyModal.ImageFile.SaveAs(path);
                        }
                    }

在视图中

<input type="hidden" value="" name="..."><input id="ImageFile" type="file" name="ImageFile" src="@Model.ImageURL">

在模态类中

 public HttpPostedFileBase ImageFile { get; set; }

在项目的Content文件夹中创建上载文件夹

通常，您还希望传递一个视图模型，而不仅仅是一个文件。在下面的代码中，您将发现一些其他有用的功能：

检查文件是否已附加检查文件大小是否为0检查文件大小是否大于4 MB检查文件大小是否小于100字节检查文件扩展名

可以通过以下代码完成：

[HttpPost]
public ActionResult Index(MyViewModel viewModel)
{
    // if file's content length is zero or no files submitted

    if (Request.Files.Count != 1 || Request.Files[0].ContentLength == 0)
    {
        ModelState.AddModelError("uploadError", "File's length is zero, or no files found");
        return View(viewModel);
    }

    // check the file size (max 4 Mb)

    if (Request.Files[0].ContentLength > 1024 * 1024 * 4)
    {
        ModelState.AddModelError("uploadError", "File size can't exceed 4 MB");
        return View(viewModel);
    }

    // check the file size (min 100 bytes)

    if (Request.Files[0].ContentLength < 100)
    {
        ModelState.AddModelError("uploadError", "File size is too small");
        return View(viewModel);
    }

    // check file extension

    string extension = Path.GetExtension(Request.Files[0].FileName).ToLower();

    if (extension != ".pdf" && extension != ".doc" && extension != ".docx" && extension != ".rtf" && extension != ".txt")
    {
        ModelState.AddModelError("uploadError", "Supported file extensions: pdf, doc, docx, rtf, txt");
        return View(viewModel);
    }

    // extract only the filename
    var fileName = Path.GetFileName(Request.Files[0].FileName);

    // store the file inside ~/App_Data/uploads folder
    var path = Path.Combine(Server.MapPath("~/App_Data/uploads"), fileName);

    try
    {
        if (System.IO.File.Exists(path))
            System.IO.File.Delete(path);

        Request.Files[0].SaveAs(path);
    }
    catch (Exception)
    {
        ModelState.AddModelError("uploadError", "Can't save file to disk");
    }

    if(ModelState.IsValid)
    {
        // put your logic here

        return View("Success");
    }

    return View(viewModel);         
}

确保你有

@Html.ValidationMessage("uploadError")

在您的视图中查看验证错误。

还要记住，默认最大请求长度为4MB（maxRequestLength=4096），要上载更大的文件，必须在web.config中更改此参数：

<system.web>
    <httpRuntime maxRequestLength="40960" executionTimeout="1100" />

（此处40960=40 MB）。

执行超时是秒的整数。您可能希望将其更改为允许上传大量文件。