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how to get and show error message from controller to view[Answered] RSS

2 replies

Last post May 19, 2020 03:00 AM by Bruce12138

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ttprettycode...

Member

5 Points

20 Posts

how to get and show error message from controller to view

May 17, 2020 11:43 PM|ttprettycoder|LINK

like the code:

View:

<body>

    @using (Html.BeginForm("ImageToPDF_Index", "ImageToPDF", FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
        <input type="file" id="postedFile" name="postedFile" multiple />
        <input type="submit" id="btnSubmit" value="Upload" />

        <div class="create-button">
            <button id="btnSubmit" onclick="doSubmit()" type="button" class="col align-self-center btn btn-primary" />submit
            @*<button id="btnCancel" onclick="goBack()" class="col-md-auto btn btn-primary">cancel</button>*@
        </div>
    }

        <div id="errorid" class="has-error">
            //here show the error files name
        </div>
</body>



@section scripts{
    <script>

        function doSubmit() {
            var form_data = new FormData($("form")[0]);

            $.ajax({
                type: "post",
                url: "@Url.Action("Index2", "ImageToPDF")",
                cache: false,
                contentType: false, 
                processData: false,
                data: form_data,
                dataType: "json",
                //error: function () {
                //    alert("fail");
                //},
                success: function (response) {
                    if (response.success == 0) {
                        alert(response);
                    }
                    else {
                        $("#errorid").append("<div>filname:" + response.filename+" "+response.msg+"</div >");
                    }
                    $("#inputdata").removeClass("notclick");
                    $("#btnstart").removeAttr("disabled");
                }

            });
        }
    </script>
}

controller:

public ActionResult ImageToPDF_Index()
        {
            return View();
        }

 [HttpPost]
        [ValidateInput(false)]
        public JsonResult Index2(IEnumerable<HttpPostedFileBase> postedFile)
        {

            List<string> errorfiles = new List<string>();
            var flag = 0;
            string errormassage = "";


            try
            {
...here handle postedFile files
}
catch (Exception e)
            {
                flag = 1;
                errormassage = e.Message;
                errorfiles.Add("error filename is:xxx");//If there is an exception in the processed file, how to record this file and display it on the View
            }

            if (flag == 0)
            {
                // return Json("success", JsonRequestBehavior.AllowGet);
                return Json(new { success = flag, msg = "success" }, JsonRequestBehavior.AllowGet);
            }
            else
            {
                return Json(new { success = flag, msg = errormassage ,filename= errorfilename }, JsonRequestBehavior.AllowGet);

            }
        }

If there are other ways to achieve the same purpose, it is also very welcome.

Thanks.

Bruce12138

Member

61 Points

21 Posts

Re: how to get and show error message from controller to view

May 19, 2020 02:39 AM|Bruce12138|LINK

Hi , ttprettycoder

From your code, I think you want to realize a function that can upload multiple files and show success or error, but there are some problems in your code.

Actually, if you want to post data by beginform, beginform can't receive data form controller and show result. even though writing ajax. Ajax will not work in beginform, that is why the "submit" button doesn't work but "upload" button can click and post data.

If you want to post data by ajax without beginform, the controller will not get the instance of object.

To realize the function, I recommend using "ViewBag". Here‘s the code.

Your view:

<body>

        @using (Html.BeginForm("Index2", "ImageToPDF", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {
            <input type="file" id="postedFile" name="postedFile" multiple />
            <input type="submit" id="btnSubmit" value="Upload" />

            <div class="create-button">
                <button id="btnSubmit" onclick="doSubmit()" type="button" class="col align-self-center btn btn-primary" />submit
                @*<button id="btnCancel" onclick="goBack()" class="col-md-auto btn btn-primary">cancel</button>*@
            </div>

            <ul>
                @if (ViewBag.result != null)
                {
                    foreach (var result in ViewBag.result)
                    {
                        <li>@result</li>
                    }

                }
            </ul>
        }
        @*
        <div id="errorid" class="has-error">
             //here show the error files name
        </div>*@
    </body>

I removed your js and used Viewbag to show result about uploading.

Your controller:

public ActionResult ImageToPDF_Index()
        {
            return View();
        }

        [HttpPost]
        [ValidateInput(false)]
        public ActionResult Index2(IEnumerable<HttpPostedFileBase> postedFile)
        {

             //List<string> errorfiles = new List<string>();
               List<string> results = new List<string>(); //it used to store every result of file
              //var flag = 0;
               string errormassage = "";
               foreach (var postfile in postedFile) 
               {
                   string filename = postfile.FileName;  //get the name of file you upload
                   string fileExtension = Path.GetExtension(filename); //File extension,it is unnecessary,you can delete it if you wany

                try
                   {
                       string filePath = Server.MapPath("~/Uploads"); //This is the directory to which you want to upload the file                       if (!Directory.Exists(filePath))
                    {
                           Directory.CreateDirectory(filePath);//create the directory
                       }
                       postfile.SaveAs(Path.Combine(filePath, filename));
                    results.Add(filename+"-success"); //upload success
                   }
                   catch (Exception e)
                   {
                     //  flag = 1;
                       errormassage = e.Message;
                      // errorfiles.Add(filename);//If there is an exception in the processed file, how to record this file and display it on the View
                    results.Add(filename + "errormassage");
                }
               }
                ViewBag.result = results;   //all result of files
                return View("ImageToPDF_Index");
        }

Viewbag will transfer the result of every file.

I have tested it to upload many images at once and success.

Best regards.

Bruce12138

Bruce12138

Member

61 Points

21 Posts

Re: how to get and show error message from controller to view

May 19, 2020 03:00 AM|Bruce12138|LINK

Hi ,ttprettycoder

From your code,I think you want to realize a function that can upload multiple files and show success or error, but there are some problems in your code.

Actually, if you want to post data by beginform,beginform can't receive data from controller and show result.,even though writing ajax.Ajax will not work in beginform, that is why the "submit" button doesn't work but "upload" button can click and post data.

If you want to post data by ajax without beginform, the controller will not get the instance of object.

To realize the function, I recommend using "ViewBag" ，here's the result.

View

<body>

        @using (Html.BeginForm("Index2", "ImageToPDF", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {
        }
            <input type="file" id="postedFile" name="postedFile" multiple />
            <input type="submit" id="btnSubmit" value="Upload" />

            <div class="create-button">
                <button id="btnSubmit" onclick="doSubmit()" type="button" class="col align-self-center btn btn-primary" />submit
                @*<button id="btnCancel" onclick="goBack()" class="col-md-auto btn btn-primary">cancel</button>*@
            </div>

            <ul>
                @if (ViewBag.result != null)
                {
                    foreach (var result in ViewBag.result)
                    {
                        <li>@result</li>
                    }

                }
            </ul>
        @*
        <div id="errorid" class="has-error">
             //here show the error files name
        </div>*@
    </body>

I removed your js and used Viewbag to show result about uploading.

Controller

public ActionResult ImageToPDF_Index()
        {
            return View();
        }

        [HttpPost]
        [ValidateInput(false)]
        public ActionResult Index2(IEnumerable<HttpPostedFileBase> postedFile)
        {

             //List<string> errorfiles = new List<string>();
               List<string> results = new List<string>(); //it used to store every result of file
              //var flag = 0;
               string errormassage = "";
               foreach (var postfile in postedFile) 
               {
                   string filename = postfile.FileName;  //get the name of file you upload
                   string fileExtension = Path.GetExtension(filename); //File extension,it is unnecessary,you can delete it if you wany

                try
                   {
                       string filePath = Server.MapPath("~/Uploads"); //This is the directory to which you want to upload the file                       if (!Directory.Exists(filePath))
                    {
                           Directory.CreateDirectory(filePath);//create the directory
                       }
                       postfile.SaveAs(Path.Combine(filePath, filename));
                    results.Add(filename+"-success"); //upload success
                   }
                   catch (Exception e)
                   {
                     //  flag = 1;
                       errormassage = e.Message;
                      // errorfiles.Add(filename);//If there is an exception in the processed file, how to record this file and display it on the View
                    results.Add(filename + "errormassage");
                }
               }
                ViewBag.result = results;   //all result of files
                return View("ImageToPDF_Index");
        }

Viewbag will transfer the result of every file.

I have tested it to upload many images at once and success.

Best regards.

Bruce12138

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