The controller for ASPxUploadProgressHandlerPage.ashx was not found or does not implement IController

• Aug 30, 2023

Error Description:

This error can occur when you upload a file (in advanced upload mode) for the following extensions that use the ASPxUploadProgressHttpHandler:

• UploadControlExtension
• BinaryImageEditExtension
• FileManagerExtension
• HtmlEditorExtension
• Office components (RichEditExtension, SpreadsheetExtension)

Solution:

Try one of the following suggestions to overcome this issue:

• Register the ASPxUploadProgressHttpHandler in the web.config file as described in the following help topic: ASPxUploadProgressHttpHandler Registration.

• Add the “*.ashx” file extension to route exceptions in the Global.asax or RouteConfig file if you use routing (for example, the Microsoft.AspNet.FriendlyUrls library).