如何在Javascript中将byte [] /内存流绑定到image src属性

Question

I have an ActionMethod which can return a Memorystream or byte[] of an image. This action method is called on ajax. Now I want to bind this image to an image tag src attribute.

public ActionResult GetBpChart(string Timespan)
    {
        var ObjMemoryStream = new MemoryStream();
        try
        {
            ObjMemoryStream = MyModel.GetImage(Timespan);
        }
        catch (Exception Ex)
        {

        }
        //return Content(Convert.ToBase64String(ObjMemoryStream.GetBuffer()));
        //return Json(ObjMemoryStream.GetBuffer());
        return File(ObjMemoryStream.GetBuffer(), "image/jpeg");
    }

function GetChart() {
try {
    $.ajax({
        type: 'POST',
        url: "myActionMethodurl",
        data: {
            Timespan: $('#ddlBpTimespan').val()
        },
        success: function (ImgSrc) {
            // For Base64String
            //$('#divBpChart').innerHTML = '<img src= "data:image/jpeg;base64," ' + ImgSrc + '"/>';
            // For Json of byte[]
            //$('#divBpChart').innerHTML = '<img src= "data:image/gif;base64," ' + ImgSrc + '"/>';
            // For FileContentResult
            $('#imgBpChart').attr('src', ImgSrc);
            HideAjaxProgress();
        }
    });

} catch (E) {
} 
}

I tried the above 3 combinations. But no luck. Can someone say what I am missing here or what's the correct way to achieve this

Answer 1

From reading the .ajax() docs, I would say the simple answer is " no, you can't do that. "

Luckily, you don't need to. Just create the relevant URL and update the target image's src attribute:

function GetChart() {
    try {
        var ImgSrc = '/mycontroller/myActionMethodurl?timespan=' + $('#ddlBpTimespan').val();
        $('#imgBpChart').attr('src', ImgSrc);
    } catch (error) {
    } 
}

If you're coding this within a View, you can leverage the UrlHelper to help build the correct "base" URL:

function GetChart() {
    try {
        var ImgSrc = '@Url.Action("myActionMethodurl", "mycontroller")?timespan=' + $('#ddlBpTimespan').val();
        $('#imgBpChart').attr('src', ImgSrc);
    } catch (error) {
    } 
}

Perhaps a better alternative?

For a plain JavaScript method that seems to work, refer to Using jQuery's ajax method to retrieve images as a blob .