Question

I’m trying to redirect all errors on the server back to my application so it can display appropriate content and potentially redirect the user to the correct location.

IIS 7 Manager added this section to my web.config when I edited the error pages through it.

<httpErrors errorMode="Custom">
    <remove statusCode="401" subStatusCode="-1" />
    <remove statusCode="403" subStatusCode="-1" />
    <remove statusCode="405" subStatusCode="-1" />
    <remove statusCode="406" subStatusCode="-1" />
    <remove statusCode="412" subStatusCode="-1" />
    <remove statusCode="502" subStatusCode="-1" />
    <remove statusCode="501" subStatusCode="-1" />
    <remove statusCode="500" subStatusCode="-1" />
    <error statusCode="404" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="500" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="501" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="502" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="412" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="406" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="405" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="403" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
    <error statusCode="401" prefixLanguageFilePath="" path="/ErrorPage.aspx" responseMode="ExecuteURL" />
</httpErrors>

However now when I try to debug in ASP.Net I get an error message. “Unable to start debugging on the web server. See help for common configuration errors. Running the web page outside of the debugger may provide further information. Make sure the server is operating correctly. Verify there are no syntax errors in web.config by doing a Debug.Start Without Debugging. You may also want to refer to the ASP.NET and ATL Server debugging Topic in the online documentation.”. This happens whether the settings are in web.config or the servers applicationHost.config.

Doing the Debug.Start without debugging provides no helpful information, the site runs as normal.

Starting debugging with the section removed from the web.config allows it to start correctly. Strangely I can add this section back in to web.config after the debugger has started and everything works as expected.

I assume its happening cause asp.net debugger doesn’t know about the IIS config section. Its really quite a pain to keep removing this section and adding it back in. Anyone know how to solve it?

Answer 1

Finally found a reasonable work around. Set everything in the IIS Server configuration (though this would work for a seperate site as well). Set the feature settings to “Detailed errors for local requests and custom error pages for remote requests”.

When we need to debug the error page itself switch it to custom errors after you have started debugging.