使用jQuery和AJAX的ASP NET上传图像

Question

What I'm trying to do is theoretically simple: I want upload an image using ASP.NET, jQuery and AJAX, without submitting a form (this part is important).

So I have this:

HTML

<input type="file" accept="image/*" id="imguploader">   

jQuery

var file_data = $("#imguploader").prop("files")[0];
var form_data = new FormData();
form_data.append("file", file_data);

        $.ajax({
            type: "POST",
            url: '@Url.Action("InsertImage", "Product")',
            data: { file: form_data },
            contentType: false,
            processData: false,
            success: function (response) {
                alert('succes!!');
            },
            error: function (error) {
                alert("errror");
            }
        });

Controller

public ActionResult InsertImage(HttpPostedFileBase file) {

   //blabla and the code to insert in the database.

   return Content("");
}

What else I have tried:

// instead of using FormData, I tried to direclty capture the file using these:

var file = $("#imguploader").file;
//and
var file = $("#imguploader")[0].files;

//Same result (null).

The problem is that the file variable is always null no matter what. What I'm doing wrong? Can anybody helps?

Answer 1

You can manually set the FormData keys and values yourself.

<input type="file" name="imguploader" id="imguploader" />
<button id="btnUpload">Upload</button>

Create FormData and set a new key/value

$("#btnUpload").on("click", function(e) {
    e.preventDefault();

    var file = $("#imguploader").get(0).files[0];
    var formData = new FormData();
    formData.set("file", file, file.name);

    $.ajax({
        url: '@Url.Action("InsertImage", "Product")',
        method: "post",
        data: formData,
        cache: false,
        contentType: false,
        processData: false
    })
    .then(function(result) {

    });
});

The controller

[HttpPost]
public ActionResult InsertImage(HttpPostedFileBase file)
{

}

Answer 2

Another way to do that.

View

@using (Html.BeginForm("Upload", "Home", FormMethod.Post, 
          new { id = "myForm", enctype = "multipart/form-data" }))
{
    <input id="file" type="file" name="file" />
    <input type="submit" value="submit" />
}
<input type="button" value="Upload" onclick="uploadFile();" />

Javascript

function uploadFile() {
    $.ajax({
        url: '@Url.Action("InsertImage", "Product")',
        type: 'POST',
        data: new FormData(myForm),
        cache: false,
        contentType: false,
        processData: false,
        success: function () {
            alert('file uploaded');
        },
        error: function (xhr, error, status) {
            console.log(error, status);
        }
    });
}

Controller

[HttpPost]
public ActionResult InsertImage()
{
    for (int i = 0; i < Request.Files.Count; i++)
    {
        var file = Request.Files[i];
        // save file into Db
    }
    return new EmptyResult();
}