return 从 c# 中的 ashx 处理程序返回到 ajax 的响应

Question

在我的应用程序中，我使用一个 ashx 处理程序来下载 ppt，因为我将创建一个屏幕截图（当前屏幕作为图像）并将该图像名称从 jquery 传递给一个处理程序（ashx）。但是我无法跟踪下载状态。

如果有任何方法 return 从该处理程序到 jquery 的响应。那就是我想知道什么时候下载完成。

我现在的场景是这样的

jquery 将生成一个 base64 字符串并通过 ajax 调用将该字符串传递给后台代码以将其转换为图像并将该图像保存在一个位置
在 ajax 请求成功调用后，它将获取该图像名称并将该图像名称传递给处理程序
我正在使用 "window.location.href"

我的代码

Ajax调用保存图片

   $.ajax({
            type: "POST",
            url: AQ.AMT.Url + "/Home/StoreImage",
            //async: false,
            data: "{'base64':'" + base64 + "'}",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (Data) {
                window.location.href = "~/Download/Export.ashx?Type=PPT&downloadToken=" + Data.Result + "&Summary=" + summaryText + "&Note=" + noteText + "&Name=" + name + "&Sample=" + sampleSize + "&SampleColor=" + sampleColor + "&pptType=" + pptType + "&flipName=" + flipName;
              //here i need some response
            },
            error: function (e) {
            }
        });

下载ppt的处理代码

 public void ProcessRequest(HttpContext context)
    {
        DownloadPPT(context);
    }
 public void DownloadPPT(HttpContext context)
    {
      //here i will take all parameters 
      try{
          //downloading the ppt
          saveFile(pres, "" + name + "-" + FlipName + "-" + System.DateTime.Today.ToLongDateString());//ppt name
         }
        catch{

             }
          finally
            {
            //after ppt download i am deleting that screenshot
            if (File.Exists(path))
                File.Delete(path);

             }  
    }

Answer 1

我找到了一个解决方案，我没有使用处理程序下载文件，而是使用 ajax 和 jquery。在后面的代码中，我将创建 ppt 并将 ppt 保存在某个文件夹中，然后将该名称传递给 ajax 响应并使用锚标记在客户端本身启用下载。

正在保存 ppt

 [HttpPost]
    public JsonResult StoreImage(ExportToPPtRequest request)
    {
        ExportPptString obj = new ExportPptString();
        string downloadToken = Guid.NewGuid().ToString();
        string filepath = Server.MapPath("~/Download/Temp/" + downloadToken + ".png");
        try
        {
            using (MemoryStream ms = new MemoryStream(Convert.FromBase64String(request.Base64)))
            {
                using (System.Drawing.Bitmap bm2 = new System.Drawing.Bitmap(ms))
                {
                    //bm2.Save(filepath);

                    downloadToken = "";

                    downloadToken=DownloadPPT(bm2,request);
                   // bm2.Dispose();
                }
               // ms.Close();
            }

            obj.Result = downloadToken;

        }
        catch (Exception ex)
        {

        }
        var result = Json(obj, JsonRequestBehavior.AllowGet);
        return result;
    }

    public string DownloadPPT(Image imgToReplace, ExportToPPtRequest request)
    {

         string summaryText = request.Summary;
         string note = request.Note;
         string sampleSize = request.SampleSize;
         string SampleColor = request.SampleColor;
         string Type = request.Type;
         string name = request.Name;
         string pptName = "";
         try
        {
            //if (downloadToken == string.Empty || downloadToken == null)
            //    throw new Exception("Download Token is unavailable.");

            Aspose.Slides.License license = new Aspose.Slides.License();
            license.SetLicense("Aspose.Slides.lic");
            var _tempPPT = "";
                _tempPPT = Server.MapPath("~/Download/Template/ExportPPt.pptx");

            Aspose.Slides.Presentation pres = new Aspose.Slides.Presentation(_tempPPT);


          pptName= saveFile(pres);//ppt name

        }
        catch (Exception ex)
        {

        }

        return pptName;

    }
    public  string saveFile(Aspose.Slides.Presentation pres)
    {

        string downloadToken = Guid.NewGuid().ToString();
        try
        {
            //MemoryStream objMemoryStream = new MemoryStream();
            //pres.Save(objMemoryStream, Aspose.Slides.Export.SaveFormat.Pptx);
            pres.Save(Server.MapPath("~/Download/Temp/" + downloadToken + ".pptx"), Aspose.Slides.Export.SaveFormat.Pptx);
            //byte[] buffer = objMemoryStream.ToArray();
            //HttpContext.Current.Response.Clear();
            //HttpContext.Current.Response.Buffer = true;
            //HttpContext.Current.Response.AddHeader("Content-disposition", String.Format("attachment; filename=\"{0}.pptx\"", PresentationName));
            //HttpContext.Current.Response.ContentType = "application/vnd.openxmlformats-officedocument.presentationml.presentation";
            //HttpContext.Current.Response.AddHeader("Content-Length", buffer.Length.ToString());
            //HttpContext.Current.Response.BinaryWrite(buffer);
            //HttpContext.Current.Response.Flush();
            //HttpContext.Current.Response.Close();


        }
        catch (Exception ex)
        {
        }
        return downloadToken;
    }

在jquery

$.ajax({
        type: "POST",
        url: AQ.AMT.Url + "/Home/StoreImage",
        //async: false,
        data: JSON.stringify({ request: request }),
        contentType: "application/json; charset=utf-8",
        dataType: "json", 
        success: function (Data) {

            var _tempPPT = AQ.AMT.Url + "/Download/Temp/" + Data.Result + ".pptx";
            // Trick for making downloadable link
            a = document.createElement('a');
            a.href = _tempPPT;// window.URL.createObjectURL(xhttp.response);
            a.id = "idanchrPPT";
            // Give filename you wish to download
            var today = new Date();
            var dd = today.getDate();
            var mm = today.getMonth() + 1; //January is 0!
            var yyyy = today.getFullYear();
            if (dd < 10) {
                dd = '0' + dd
            }
            if (mm < 10) {
                mm = '0' + mm
            }
            today = dd + '/' + mm + '/' + yyyy;
            if (flipName == "")
                a.download = "" + name + "-" + today + ".pptx";
            else
            a.download = "" + name + "-" + flipName + "-" + today + ".pptx";
            a.style.display = 'none';
            document.body.appendChild(a);
            a.click();
            $("#idanchrPPT").remove();


            //deleting the file
            var deleteFiles = {};
            deleteFiles.FilePath = Data.Result;
            setTimeout(function () {
                $.ajax({
                    type: "Post",
                    data: JSON.stringify({ deleteFiles: deleteFiles }),
                    url: AQ.AMT.Url + "/Home/DeleteExportedPPt",
                    async: true,
                    contentType: "application/json; charset=utf-8",
                    dataType: "json",
                    success: function (result) {
                    },
                    error: function (result) {
                    }
                });
            }, 1000);
        },
        error: function (e) {
        }
    });

return 从 c# 中的 ashx 处理程序返回到 ajax 的响应

return response back to ajax from ashx handler in c#

asp.net

ajax

post

httphandler

ashx