c# - XML System.InvalidOperationException: Duplicate attribute -

the idea need return list of announcements , list of videos string web service. i'm having problems putting lists xml schema.

here's xml schema:

<?xml version="1.0" encoding="utf-8"?> <xs:schema id="welcomescreenschema"     elementformdefault="qualified"     xmlns:xs="http://www.w3.org/2001/xmlschema">   <xs:attribute name="id" type="xs:int"/>   <xs:attribute name="added" type="xs:datetime"/>    <xs:element name="welcomescreen">     <xs:complextype>       <xs:all>         <xs:element ref="announcements" maxoccurs="1" minoccurs="1" />         <xs:element ref="videos" maxoccurs="1" minoccurs="1" />       </xs:all>     </xs:complextype>   </xs:element>    <xs:element name="announcements">     <xs:complextype>       <xs:sequence>         <xs:element ref="announcement" maxoccurs="unbounded" minoccurs="0"/>       </xs:sequence>     </xs:complextype>   </xs:element>    <xs:element name="videos">     <xs:complextype>       <xs:sequence>         <xs:element ref="video" maxoccurs="unbounded" minoccurs="0"/>       </xs:sequence>     </xs:complextype>   </xs:element>    <xs:element name="announcement">     <xs:complextype>       <xs:attribute ref="id" use="required"/>       <xs:attribute ref="added" use="required"/>       <xs:attribute name="html" type="xs:string" use="required"/>     </xs:complextype>   </xs:element>    <xs:element name="video">     <xs:complextype>       <xs:attribute ref="id" use="required"/>       <xs:attribute ref="added" use="required"/>       <xs:attribute name="url" type="xs:string" use="required"/>       <xs:attribute name="title" type="xs:string" use="required"/>       <xs:attribute name="description" type="xs:string" use="required"/>     </xs:complextype>   </xs:element> </xs:schema> 

i'm populating data using following c#:

xmlobject result = new xmlobject("c:\path\to\schema.xsd");  result.add(new xelement("welcomescreen")); result.root.add(new xelement("announcements")); result.root.add(new xelement("videos"));  result.root.element("announcements").add(new xelement("announcement",     new xattribute("id", convert.tostring(id)),     new xattribute("html", html),     new xattribute("added", added) ));  result.root.element("videos").add(new xelement("video",     new xattribute("id", convert.tostring(id)),     new xattribute("html", url),     new xattribute("html", title),     new xattribute("html", description),     new xattribute("added", added) )); 

the lines add announcement , video elements, inside loops i'm reading info database, excluded code brevity.

it loads 3 announcement elements schema without problem. when tries load first video element, crashes giving following error:

system.exception unhandled   hresult=-2146233088   message=error getting welcome screen info db. : system.invalidoperationexception: duplicate attribute.    @ system.xml.linq.xelement.addattributeskipnotify(xattribute a)    @ system.xml.linq.xcontainer.addcontentskipnotify(object content)    @ system.xml.linq.xcontainer.addcontentskipnotify(object content) 

you adding same attribute multiple times, not allowed

result.root.element("videos").add(new xelement("video", new xattribute("id", convert.tostring(id)), new xattribute("html", url), new xattribute("html", title), new xattribute("html", description), new xattribute("added", added)