Question

I’m using mvc3 razor engine

from view I call function with Uri.Action which return FilecontentResult

 <img src="@Url.Action("GetImg", "Controller", new { id = Model.Id })" alt="Person Image" /> 

Function:

  public FileContentResult GetImg(int id)
            {
                var byteArray = _context.Attachments.Where(x => x.Id == id).FirstOrDefault();
                if (byteArray != null)
                {
                    return new FileContentResult(byteArray.Content, byteArray.Extension);
                }
                    return null;
            }

if byteArray is empty function returns null

how to know from view what returned function?

I need something like this

    if(byteArray == null)
      <img src="default img" alt="Person Image" />     
    else
     {
  <a class="highslide" href="@Url.Action("GetImg", "Controller", new { id = Model.Id })" id="thumb1" onclick="return hs.expand(this)">
                        <img src="@Url.Action("GetImg", "Controller", new { id = Model.Id })" alt="Person Image" /> </a>    
      }

Answer 1

public ActionResult GetImg(int id)
{
    var byteArray = _context.Attachments.Where(x => x.Id == id).FirstOrDefault();
    if (byteArray == null)
    {
        // we couldn't find a corresponding image for this id => fallback to the default
        var defaultImage = Server.MapPath("~/images/default.png");
        return File(defaultImage, "image/png");
    }
    return File(byteArray.Content, byteArray.Extension);
}

and in your view simply:

<img src="@Url.Action("GetImg", "Controller", new { id = Model.Id })" alt="Person Image" /> 

or if you write a custom HTML helper to generate this <img> tag even simpler:

@Html.PersonImage(Model.Id)