How to send additional attributes with the upload control

I am trying to send additional attributes with the upload control. but my controller does not pick up the ActNo

 <RadzenUpload Icon="upload"
               ChooseText=""
               Url="upload/file"
               Progress=@(args => OnProgress(args, "uploadfile"))
               Style="width: 100%"
               InputAttributes="@(new Dictionary<string, object>() { { "ActNo", $"{actor.ActNo}" }})">
 </RadzenUpload>

 public async Task<IActionResult> UploadFile([FromForm] IFormFile file, [FromForm] int ActNo)
 {

     if (ActNo == 0) {
         throw new ArgumentException("Actor cannot be 0");
     }
}

any ideas how to achieve this?

There is a demo showing exactly this and it’s not using InputAttributes.

I guess you need this, but it does not explain how to pick it up in the controller

    <RadzenUpload Multiple="true" Accept="image/*" Url=@($"upload/{customParameter}") Progress=@(args => OnProgress(args, "Upload with additional parameter")) Style="width: 100%" InputAttributes="@(new Dictionary<string,object>(){ { "aria-label", "select file" }})" />

You can check and debug the code of the upload controller if you run the demos locally:

can you make out anything from this?

if I removed the "multiple" prop the upload worked

You need to ensure the controller action file parameter type and name match.
image