Validation

RadCloudUpload offers a built-in option to validate the file size and extension on Client-side.

For Server-side validation, you will need to implement a Custom Provider and validate the files manually.

Usage

To validate the file size and extension, set the following properties:

• MaxFileSize - the maximum allowed size
• AllowedFileExtensions - one or more allowed extensions separated by comma

Example

ASP.NET

<telerik:RadCloudUpload ID="RadCloudUpload1" runat="server" 
  MaxFileSize="500 kB" 
  AllowedFileExtensions=".png,.jpg" >
</telerik:RadCloudUpload>

When the validation fails, CloudUpload triggers the OnClientValidationFailed Client-side event. To send a feedback to the user (alert, etc.), you can do so inside this event.

Custom Validation

In addition to the built-in validation, you can add custom validations by utilizing some of the Client-side events of RadCloudUpload.

Allowed number of uploaded files

You can limit the maximum number of files that can be uploaded, by counting them in the OnClientFileUploading event handler, and canceling the event to prevent uploading more than the number of files allowed.

Markup

ASP.NET

<telerik:RadCloudUpload ID="RadCloudUpload1" runat="server" 
  MultipleFileSelection="Automatic" 
  OnClientFileUploading="OnClientFileUploading">
</telerik:RadCloudUpload>

JavaScript

JavaScript

function OnClientFileUploading(sender, args) {
  var filesCount = sender.get_uploadedFiles().length,
  maxFilesCount = 3;

  if (filesCount > maxFilesCount) {
	args.set_cancel(true);
	alert('You cannot select more than: ' + maxFilesCount);
  }
}