我正在努力让它工作，但我在上传文件时遇到错误。

ASPX

<asp:FileUpload ID="FileUpload1" runat="server" CssClass="file-upload-dialog" />
<asp:Button runat="server" ID="btnUpload" CssClass="btn upload" Text="Upload" />

Handler

public void ProcessRequest(HttpContext context)
      {
            context.Response.ContentType = "multipart/form-data";
            context.Response.Expires = -1;
            try
            {
                  HttpPostedFile postedFile = context.Request.Files["file"];
                  string savepath = HttpContext.Current.Server.MapPath("~/assets/common/CompetitionEntryImages/");
                  var extension = Path.GetExtension(postedFile.FileName);

                  if (!Directory.Exists(savepath))
                        Directory.CreateDirectory(savepath);

                  var id = Guid.NewGuid() + extension;
                  if (extension != null)
                  {
                        var fileLocation = string.Format("{0}/{1}",
                                                         savepath,
                                                         id);

                        postedFile.SaveAs(fileLocation);
                        context.Response.Write(fileLocation);
                        context.Response.StatusCode = 200;
                  }
            }
            catch (Exception ex)
            {
                  context.Response.Write("Error: " + ex.Message);
            }
      }

Jquery

$(document).ready(function () {
            email = $("input[id$='emailHV']").val();
            alert(email);
            $('#aspnetForm').attr("enctype", "multipart/form-data");
      });



$('#<%= btnUpload.ClientID %>').on('click', function (e) {
            e.preventDefault();
            var fileInput = $('#ctl00_PageContent_Signup_ctl06_MWFileUpload_FileUpload1');
            var fd = new window.FormData();
            fd.append('file', fileInput.files[0]);

            $.ajax({
                  url: '/charity-challenge/MWFileUploadHandler.ashx',
                  data: fd,
                  processData: false,
                  contentType: false,
                  type: 'POST',
                  success: function (data) {
                        alert(data);
                  }
            });
      });

Error

HTML

<input type="file" name="ctl00$PageContent$Signup$ctl06$MWFileUpload$FileUpload1" id="ctl00_PageContent_Signup_ctl06_MWFileUpload_FileUpload1" class="file-upload-dialog">

 <input type="submit" name="ctl00$PageContent$Signup$ctl06$MWFileUpload$btnUpload" 
value="Upload" onclick="javascript:WebForm_DoPostBackWithOptions(new 
WebForm_PostBackOptions(&quot;ctl00$PageContent$Signup$ctl06$MWFileUpload$btnUpload&quot;, 
&quot;&quot;, true, &quot;&quot;, &quot;&quot;, false, false))" 
id="ctl00_PageContent_Signup_ctl06_MWFileUpload_btnUpload" class="button">

EDITS

最后，我通过做这些事情来形成数据来让它工作

var fileData = fileInput.prop("files")[0];   // Getting the properties of file from file field
        var formData = new window.FormData();                  // Creating object of FormData class
        formData.append("file", fileData); // Appending parameter named file with properties of file_field to form_data
        formData.append("user_email", email);

完整的工作代码

$('#<%= btnUpload.ClientID %>').on('click', function (e) {
            e.preventDefault();
            var fileInput = $('#<%= FileUpload1.ClientID %>');
            var fileData = fileInput.prop("files")[0];   // Getting the properties of file from file field
            var formData = new window.FormData();                  // Creating object of FormData class
            formData.append("file", fileData); // Appending parameter named file with properties of file_field to form_data
            formData.append("user_email", email);
            $.ajax({
                  url: '/charity-challenge/MWFileUploadHandler.ashx',
                  data: formData,
                  processData: false,
                  contentType: false,
                  type: 'POST',
                  success: function (data) {
                        var obj = $.parseJSON(data);
                        if (obj.StatusCode == "OK") {
                              $('#<%= imagePath.ClientID %>').val(obj.ImageUploadPath);
                              $('.result-message').html(obj.Message).show();
                        } else if (obj.StatusCode == "ERROR") {
                              $('.result-message').html(obj.Message).show();
                        }
                  },
                  error: function (errorData) {
                        $('.result-message').html("there was a problem uploading the file.").show();
                  }
            });
      });

经过一整个下午的敲打，当我意识到你指定了“处理程序”而不是“服务”时，我回到了这个问题/解决方案，差别很大。 :) 另外，对于可以在后面运行此 jquery 的工作处理程序，我去了https://github.com/superquinho/jQuery-File-Upload-ASPnet https://github.com/superquinho/jQuery-File-Upload-ASPnet并剪掉了我不需要的东西。这是我正在使用的处理程序代码（VS2012）。正如你所看到的，我现在只使用它来上传 csv。

Imports System
Imports System.Web
Imports System.Data

Public Class FileUpload : Implements IHttpHandler, IReadOnlySessionState
    Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
        Try
            Select Case context.Request.HttpMethod
                Case "POST"
                    Uploadfile(context)
                    Return

            Case Else
                context.Response.ClearHeaders()
                context.Response.StatusCode = 405
                Return
        End Select

    Catch ex As Exception
        Throw
    End Try

End Sub

Private Sub Uploadfile(ByVal context As HttpContext)

    Dim i As Integer
    Dim files As String()
    Dim savedFileName As String = String.Empty
    Dim js As New Script.Serialization.JavaScriptSerializer

    Try

        If context.Request.Files.Count >= 1 Then

            Dim maximumFileSize As Integer = ConfigurationManager.AppSettings("UploadFilesMaximumFileSize")

            context.Response.ContentType = "text/plain"
            For i = 0 To context.Request.Files.Count - 1
                Dim hpf As HttpPostedFile
                Dim FileName As String
                hpf = context.Request.Files.Item(i)

                If HttpContext.Current.Request.Browser.Browser.ToUpper = "IE" Then
                    files = hpf.FileName.Split(CChar("\\"))
                    FileName = files(files.Length - 1)
                Else
                    FileName = hpf.FileName
                End If


                If hpf.ContentLength >= 0 And (hpf.ContentLength <= maximumFileSize * 1000 Or maximumFileSize = 0) Then
                    Dim d As Date = Now
                    savedFileName = HttpRuntime.AppDomainAppPath & "CSVLoad\" + d.Year.ToString + d.DayOfYear.ToString + d.Hour.ToString + d.Minute.ToString + d.Second.ToString + d.Millisecond.ToString + ".csv"

                    hpf.SaveAs(savedFileName)

                Else

                End If
            Next

        End If

    Catch ex As Exception
        Throw
    End Try

End Sub

Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
    Get
        Return False
    End Get
End Property

End Class