Stop Upload before it starts

Hello, I have a Upload control that depends on some other fields on the webpage being set to a certain values before it starts the upload.  When I click the asp submit button I check these values server side and if they are not set proper I display a message and return.  THe problem is it seems the upload process starts then after some time (depending upon the size of the file) the message appears.  Can I not check the values on the page before the upload actually starts.  I tried using asp field validators but there are issues using this as I have other fields on the screen that cause postbacks this cause the validator to check the fields prematurally.

THanks Kerry

Hi Kerry,

The file upload will start as soon as there is a postback. So, you need to perform your custom checks using javascript before the form is submitted.
You can use asp.net validators and set the CausesValidation property to False on those controls which should not cause validation.

Best wishes,
Veselin Vasilev
the Telerik team