Sys.WebForms.PageRequestManager

ParserErrorException...

Problem

You get this error when running your application:

Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed.

Application tracing is enabled

When application-level tracing is turned on, Response.Write is called to write diagnostic information which is not compatible with the smooth panel update feature (updatepanel).

Step 1:  Turn off application tracing (Build, Tracing and Event Logging…).

Step 2:  Re-build your application (Build, Rebuild All).

Step 3:  Run your application.

Conflicts with Smooth Panel Update

You may have a button, frequently the File Download button or File Upload button, inside a table panel or record panel which is surrounded by an UpdatePanel control.  In this case, the Ajax smooth panel update feature triggers an asynchronous postback and cannot recognize the file you are uploading or downloading.

To solve this problem, trigger a traditional postback when the button is clicked by setting the PostBack property for the button to ‘True’ in the Property Sheet.

ServerErrorException

Problem

You receive this error message when attempting to view a page in your application:

Sys.WebForms.PageRequestManagerServerErrorException:
An unknown error occurred while processing the request on the server.
The status code returned from the server was: 404 ...

This error occurs when the table name has foreign characters. Then clicking any button might cause a  javascript error.

Solution

To resolve this problem, go to the application generation option, General Application Options->Web Page Options->Page Controls->Smooth panel update to turn off smooth panel update.

OR:

Problem

Sys.WebForms.PageRequestManagerServerErrorException:
An unknown error occurred while processing the request on the server.
The status code returned from the server was: 500

Solution

Microsoft .Net Framework by default allows a limited number of fields, to be posted to a page, which is set to 1000. If there are more than the default number of fields posted, it results in an error. This can possibly happen when you have multiple Many-To-Many panels on the page.

To work around this issue, please add the following element to your AppSettings in your web.config:

<add key="aspnet:MaxHttpCollectionKeys" value="5000" />