Asyncfileupload file preview doesn’t show

Posted on

Problem :

I am having an Ajax Asynchronous file upload control in update panel. My upload works fine but after the upload is completed., I need to see the image I have uploaded.
But it doesnt work here is what I have done

function UploadComplete(sender, args) {
        var filename = args.get_fileName();
        var contentType = args.get_contentType();
        if (contentType.indexOf('image') == -1) {
            document.getElementById('<%=lblStatus.ClientID%>').innerText = "Uploaded file must be an Image!"+ "<span style='color:red;'>" + args.get_errorMessage() + "</span>";
            document.getElementById('<%=AsyncFileUpload1.ClientID%>') = "Red";
        else {
            var text = "" + filename + "      |      " + args.get_length() + " bytes"+"Uploaded Succesfully";
            document.getElementById('<%=lblStatus.ClientID%>').innerText = text;
              $get("imageView1").src = "./~/" + filename;


<ajaxToolkit:AsyncFileUpload ID="AsyncFileUpload1" Width="400px" runat="server"    
        CompleteBackColor="Lime" UploaderStyle="Modern"    
        ErrorBackColor="Red" ClientIDMode="AutoID"    
            onuploadedcomplete="AsyncFileUpload1_UploadedComplete" /> 

 <asp:Label ID="Throbber" runat="server" Style="display: none">
 <asp:Image runat="server" ID="imgPreview" ImageUrl="~/Images/uploading.gif" />
        <img runat="server" id="imageView1"/>
 <asp:Label ID="lblStatus" runat="server" Style="font-family: Arial; font-size: small;"></asp:Label>

Solution :

You can use the OnUploadedComplete event to display the image.

<ajaxToolkit:AsyncFileUpload ID="AsyncFileUpload1" Width="400px" runat="server" OnUploadedComplete="ProcessUpload"

protected void ProcessUpload(object sender, AjaxControlToolkit.AsyncFileUploadEventArgs e)
string fileName = Server.MapPath("./") + "image.jpg";

ScriptManager.RegisterClientScriptBlock(AsyncFileUpload1, AsyncFileUpload1.GetType(), "img",

For Details on how to show the preview take a look at this example: AJAX File Upload in ASP.NET with the AsyncFileUpload Control

I don’t think “~” will work with HTML controls. Try converting the path to actual path and set the Image src.

Leave a Reply

Your email address will not be published. Required fields are marked *