Ajax功能沒有收到來自服務器的響應

Question

本質上，我正在使用上傳器（dropzone.js）並將其合併到我的網站中。添加文件到服務器工作正常，但我有刪除它們的麻煩。我的javascript：

$(document).ready(function() { 
    Dropzone.autoDiscover = true; 
    $("#dZUpload").dropzone({ 
     url: "uploadHandler.ashx", 
     addRemoveLinks: true, 
     success: function (file, response) { 
      file.previewElement.classList.add("dz-success"); 
      console.log("Successfully uploaded: " + file.name); 
     }, 
     error: function (file, response) { 
      file.previewElement.classList.add("dz-error"); 
     }, 
     init: function() { 
      var dZUpload = this; 
      this.on("removedfile", function (file) { 
       $.ajax({ 
        type: "POST", 
        url: "uploadHandler.ashx/DeleteFile", 
        data: { filename: file.name }, 
        dataType: "json", 
        success: function (repsonse) { 
         if (data == "success") { 
          alert("Successfully deleted."); 
          this.removeFile(file); 
         } 
         else { 
          alert("Error deleting file."); 
          this.removeFile(file); 
         } 
        } 
       }); 
      }); 
     } 

    }); 
}); 

，這是對我的服務器端處理的deleteFile功能代碼：

<System.Web.Services.WebMethod()> _ 
Public Function DeleteFile(filename As String) As String 
    Try 
     Dim Yes As String = "success" 
     System.IO.File.Delete(Path.Combine(HttpContext.Current.Server.MapPath("~/serverFiles/"), filename)) 
     Return Yes 
    Catch ex As Exception 
     Dim No As String = "failure" 
     Return No 
    End Try 
End Function 

什麼應該發生：當刪除鏈接被點擊上載的文件，客戶端通過Ajax發送POST到服務器。服務器將文件從磁盤上刪除，並向客戶端發送一條消息，說這是成功的。

這是我第一次使用Ajax，發生了什麼？爲什麼不發送消息？

編輯：當我改變dataType: "json"到test我reeive以下錯誤：

Uncaught ReferenceError: data is not defined 
$.ajax.success @ fileUploader.aspx:31 

第31行是這樣的：if (data == "success") {

所以它的好一點，但我仍然不知道如何進行。

Answer 1

聲明您的Web方法爲共享（靜態）例如

Public Shared Function DeleteFile(filename As String) As String 

，然後修改您的AJAX調用：

var data = { filename: file.name } 
    $.ajax({ 
     method: "POST", 
     url: "uploadHandler.ashx/DeleteFile", 
     data: JSON.stringify(data), 
     dataType: "json", 
     contentType: "application/json; charset=utf-8", 
     success: function (repsonse) { 
      if (data == "success") { 
       alert("Successfully deleted."); 
       this.removeFile(file); 
      } 
      else { 
       alert("Error deleting file."); 
       this.removeFile(file); 
      } 
     } 
    });