Sys.WebForms.PageRequestManagerParserErrorException

How to resolve , solution for the Sys.WebForms.PageRequestManagerParserErrorException

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If you've used the Microsoft ASP.NET AJAX UpdatePanel control, there's a good chance you've hit the "Sys.WebForms.PageRequestManagerParserErrorException" error.

Solutions:

1.
Calls to Response.Write():
Place an <asp:Label> or similar control on your page and set its Text property. The added benefit is that your pages will be valid HTML. When using Response.Write() you typically end up with pages that contain invalid markup.
2.
Response filters:
The fix might just be to not use the filter. They're not used very often anyway. If possible, filter things at the control level and not at the response level.
3.
HttpModules:
Same as response filters.
4.
Server trace is enabled:
Use some other form of tracing, such as writing to a log file, the Windows event log, or a custom mechanism.
5.
Calls to Server.Transfer():
I'm not really sure why people use Server.Transfer() at all. Perhaps it's a legacy thing from Classic ASP. I'd suggest using Response.Redirect() with query string parameters or cross-page posting.


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