Following closely our customers’ feature requests and the latest browser implementations concerning the Html5 FileApi, we keep on our development tradition by adding to Telerik’s ASP.NET Async Upload five new features and support for uploading files in iPad/iPhone iOS.


From Q3.2012 RadAsyncUpload supports uploading files by dropping them not only over the upload itself but also over different DropZones on the page. This is easily achieved by setting the DropZones property which lists CSS selectors (with comma separators) allowing users to have a more intuitive functionality. More details can be found in this demo.

Manual Upload

 Another functionality that provides more flexibility in the process of Uploading files is the Manual Upload which allows you to trigger the uploading start of the selected files in the most appropriate moment for your custom scenario. This is achieved by setting the ManualUpload property to true.  In order to start the upload startUpload() method from the client side API of the Telerik’s AsyncUpload should be invoked. You can check out how it actually works here.


Query String Parameters to the Upload Handler

The ability to add query string parameters to the Upload Handler was a long time requested feature. Now by using the eventArgs of the onClientFileUploading client event one can use the set_queryStringParams()  to add information to the uploading file and retrieve it later on in the uploading process methods of the Upload Handler.  Check out an example code here.

Disable Chunk Upload

This new property DisableChunkUpload is useful in some specific scenarios where the usual way of uploading files chunk by chunk (in FileApi and Silverlight modules) should be suppressed. One example of such scenario is when a Custom Handler is used and the uploading file is not saved to the Temporary folder until its base of the Process method is called. In this case single chunk upload allows saving the file directly into a DataBase without saving it at the server side.

Application Pool Impersonation

When the UseApplicationPoolImpersonation property is set to true and in the same time the user does not have a permission to the Temporary/Target Folder, the control can impersonate the Application Pool Identity upon saving the file and this way allow an easier permission configuration. For example, such scenario is observed when a user is trying to upload a file and have no write permissions. In this case RadAsyncUpload impersonates them form the ones that are set to the Application Pool itself.

Uploading Files in IPad/IPhone IOS

This functionality was not supported by the browser itself not so long time ago and immediately after its implementation we updated the AsyncUpload accordingly.

I hope these new features will be useful for you. Your feedback on the content or ideas for new functionality in Telerik’s AsyncUpload is more than welcome.


About the Author

Plamen Zdravkov

is a Support Officer at one of Telerik's ASP.NET AJAX teams, where he is mainly responsible for RadScheduler, RadAsyncUpload and RadTreeView. He joined the company in 2011 and ever since he has been working on creating online resources and helping customers with various RadControls scenarios. Plamen's main interests are connected with Web and Mobile programming and in his free time he is keen on football and nature walks.

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