c# - error executing child request for server.transfer with Handler -

i have created handler process .html pages in asp.net c# web application. use url rewriting concepts.
handler works fine when html requrest come server/website. coding details follows:

web.config handler code:

<add verb="*" path="*.html," validate="false" type="myproject.contenthandler,myproject" /> 

contenthandler.cs code:

public void processrequest(httpcontext context) {             string strmappage = string.empty;             if (context.request.url.tostring().contains("category"))             {                 strmappage = "/links.aspx?id=" + producid;             }             else             {                 strmappage = context.request.url.tostring();             }             context.server.transfer(strmappage); } 

this method works fine .html request page http://localhost:9111/user-category-1.html when try open page '/js/tinymce/imagemanager/index.html'
throws error "error executing child request /js/tinymce/imagemanager/index.html"

how solve problem?

from microsoft:

microsoft internet information services (iis) dispatches server.transfer or server.execute request appropriate internet server application programming interface (isapi) extension based on extension of requesting file. example, request .aspx page dispatched aspnet_isapi.dll isapi extension.

after request dispatched appropriate isapi extension, isapi extension cannot call isapi extension. receive error message "error executing child request pagename.asp" because aspnet_isapi.dll file, handles requests asp.net pages, cannot forward request asp.dll file, handles requests asp pages.

your haldler creating problem,

try this: caused custom http handler being added application being run in root of web site. resolve problem, modify web.config file. after add:

<httphandlers> <clear /> <add verb="*" path="*.aspx" type="system.web.ui.pagehandlerfactory" />  </httphandlers>