As I understand, the multiple attribute, when set to false, will limit the number of files uploaded at a time to 1:

Specifies whether a user can upload more than one file simultanesouly. This value defaults to false.

Reference here.

However, even if I explicitly set this value to false, I am still able to select multiple files to upload at a time, either via the document selector window, or the drag-and-drop:

Code snippet:

    label="Attach receipt"
    accept=".pdf, .PDF, .png, .PNG, .jpg, .JPG"
    recordId="{!v.recordId} " 
    onuploadfinished="{! c.handleUploadFinished }" />

Screenshot of my simultaneous upload issue:

enter image description here

API Version

  • 41

Should I do this check in ContentDocument trigger? However I don't want to even reach the backend. I wanted to deal with all these conditions in the frontend.

  • 2
    That looks like a bug to me .Have you filed a case with support ? Feb 1 '18 at 2:22

After hours of pain, I found a workaround.

Before this workaround, the lightning fileupload component creates an html like this:

<input type="file" id="input-1" aria-labelledby="input-1-form-label input-1-file-body-label" accept=".pdf, .jpg" multiple="" class="slds-file-selector__input slds-assistive-text">

After the workaround was implemented, the multiple="" disappeared.

The workaround is to explicitly set the multiple attribute to false in the controller.

The fileupload will look something like this (the important thing in this one is the aura:id, which will be used later):

    label="Attach receipt"
    accept=".pdf, .jpg"
    onuploadfinished="{! c.handleUploadFinished }" 
    aura:id="lightningFileUpload" />

In the component, I added a handler to the render event:

<aura:handler name="render" value="{!this}" action="{!c.onRender}"/>

Once the render event finishes, I call the fileupload component, and set its multiple attribute to false:

onRender : function(component, event, helper) {
  component.find("lightningFileUpload").set("v.multiple", false);

It's the nearest workaround I can find that doesn't involve hacking my way via css, vanillaJS, or even catching stuff in the ContentDocument trigger.

  • Woooo .That never struck to me .Thats great working around the problem .+1 from me Feb 1 '18 at 14:26

This looks like a bug to me for sure .The component outputs a HTML tag as below for the code

<lightning:fileUpload label="Attach receipt"
    onuploadfinished="{!c.handleUploadFinished}" />

This is output as below . Notice multiple attribute in the input html tag .

<input type="file" id="input-1" aria-labelledby="input-1-form-label input-1-file-body-label" accept=".pdf,.png" multiple="" name="fileUploader" class="slds-file-selector__input slds-assistive-text">

There is not lot you could do than server validation as the hooks before file upload is not exposed to you as the developer .So report as a bug to SFDC .


Sounds like SFDC has a fix .The below code is believed to work

<aura:component implements="flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId" access="global" > 
  <aura:attribute name="myRecordId" type="String" description="Record to which the files should be attached" /> 
  <aura:attribute name="multiple" type="Boolean" default="false" /> 
     <lightning:fileUpload label="Attach receipt." 
  accept=".pdf, .png" 

The controller code

    handleUploadFinished: function (cmp, event) { 
//  Get the list of uploaded files 
    var uploadedFiles = event.getParam("files"); 
    alert("Files uploaded : " + uploadedFiles.length); 

  • 2
    No you need a PROD to do that .I can raise it on your behalf tomorrow and share details if you do not have access Feb 1 '18 at 3:21
  • 1
    I would appreciate it if you can report it on my behalf. Thank you very much.
    – SamuelDev
    Feb 1 '18 at 3:22
  • 1
    Case opened for this one .The case no is 18239480 Feb 1 '18 at 3:40
  • 1
    Hi Mohith. I found a workaround, I posted it below. Hopefully the lightning team can fix this for the next release.
    – SamuelDev
    Feb 1 '18 at 14:23
  • 1
    Heard from support that this issue will be fixed and rolled out in all the orgs and sandboxes in coming days . Feb 8 '18 at 17:20

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