Sys.WebForms.PageRequestManagerServerErrorException 12031

Question

I\'m occasionaly getting the following popup from an AJAX.NET application

Sys.WebForms.PageRequestManagerServerErrorException: An Unknown error occurred while proc         


        

Answer 1

If you're getting that from an updatePanel, set EnablePartialRendering to false in the ScriptManager for the page, and then it should give you the actual error.

Also, if it only happens occasionally, I've found that it could be a viewstate problem, especially when the page goes a long time (20mins or so) between refreshes.

Otherwise, try some try/catch blocks. Those are some easy methods.

Hope that helps!

Answer 2

It's a viewstate problem, but not related with time but with size. Try playing with maxRequestLength in your web.config.

Answer 3

add <httpRuntime requestValidationMode="2.0"/>
in web.config and in YourPage.aspx set (ClientIDMode="Static" ValidateRequest="false")

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

EXAMPLE: web.config

   <?xml version="1.0"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <system.web>
    <httpRuntime requestValidationMode="2.0"/>
    <compilation debug="true" targetFramework="4.0">
      <assemblies>
        <add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
      </assemblies>
    </compilation>

  </system.web>


  <connectionStrings>
    <add name="WT_ZadnjiEntities" connectionString="metadata=res://*/DAL.Model.csdl|res://*/DAL.Model.ssdl|res://*/DAL.Model.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=SATELLITE-PC;initial catalog=WT_Zadnji;integrated security=True;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
</configuration>

Answer 4

I've got this error in UpdatePanel with autopostback Dropdown after big delay (>20 min) between change dropdown selection.

Try increase session timeout in web.cofig. For example:

<sessionState mode="InProc" cookieless="true" timeout="720"/>;

Answer 5

sometimes the error occurs if you have added a server SSL certificate(https).If the certificate is not valid it will give this error.

Answer 6

I had the following error happening on postback:

Error: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server.

But for me, the issue was that I am converting my project from ASP.NET 2.0 to ASP.NET 4.0 and I had <asp:UpdatePanel runat="server"> used on the page.

I took off the <asp:UpdatePanel runat="server"> (for the time being), then ran the page to get the exact error. Which was "A potentially dangerous Request.Form value was detected"

I found that even though I have ValidateRequest="false" on the page, ASP.NET 4.0 requires you to add requestValidationMode="2.0" in the HttpRuntime tag of web.config.

<httpRuntime maxRequestLength="102400" requestValidationMode="2.0"/>

Reference