 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
.NET Forum / ASP.NET / Web Services / December 2004PLEASE HELP - object reference not set to instance of an object
Using MSXML2.XMLHTTP to create a soap package that contains xml in the body which works perfectly well. But in the web service no matter WHAT I do in my service to reference the passed xmlnode it returns object not set to an instance of the node. This is the soap package I am sending to the service. <?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Header></soap:Header> <soap:Body> <submitContact xmlns="evententerprise"> <data> <contact address="asdfasdfasdf"> <Test>this is a test</Test> </contact> </data> </submitContact> </soap:Body> </soap:Envelope> My web service basically is as follows: <WebMethod(EnableSession:=True)> _ Public Function submitContact(ByVal data As XmlNode) As String Dim result As String Dim xe As XmlElement Try xe = data.SelectSingleNode("//Test") result = xe.Value Catch ex As Exception result = ex.Message End Try Return result End Function I have even tried place the data.outerXml into a new xmldocument and trying to reference that but no go. No matter what I do it comes back with the exception message 'Object reference not set to an instance of an object' Please help am going nuts trying to figure out what is going on!! Cheers Keith When I look at my resulting xml that is being loaded into the xmldocument within the webservice I am seeing the following: <contact xmlns="evententerprise"> <Title xmlns="evententerprise">Mr</Title> <Fname xmlns="evententerprise">Joe</Fname> <Lname xmlns="evententerprise">Bob</Lname> </contact> Is this what is causing me my problems when i try myxmldoc.selectsinglenode("//Lname") > Using MSXML2.XMLHTTP to create a soap package that contains xml in the > body which works perfectly well. But in the web service no matter WHAT I [quoted text clipped - 43 lines] > Cheers > Keith Are you sure you want //Test? Doesn't that say "Find a node named Test at the root of the document?" Another thought is you need to accommodate namespace to get the Xpath expression to find the proper node. If you serialize the XMl you receive to a file or look at it in the debugger, are you getting the node you expect? -------------------- >From: "Keith Chadwick" <webmaster-nospam@allianceevents.com> >Subject: PLEASE HELP - object reference not set to instance of an object [quoted text clipped - 9 lines] >NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >Path: cpmsftngxa10.phx.gbl!TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP09 phx.gbl >Xref: cpmsftngxa10.phx.gbl microsoft.public.dotnet.framework.aspnet.webservices:26866 >X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webservices > [quoted text clipped - 44 lines] >Cheers >Keith Been trying everything Dan with no luck. Have done the following: Public Function submitContact(ByVal data As XmlNode) As xmldocument Dim result As String Dim resultDoc as new XmlDocument resultDoc.loadxml("<root>" & data.innerXML() & "</root>") return resultDoc End The xml comes back fine the same way I sent it down!!! But if I do anything like myElement=resultDoc.selectSingleNode("ROOT/contact/Title") it allways allways no matter what comes back with the same error that I did not create a new instance when I try to get at the element. I tried a test=resultDoc.selectNodes("ROOT/contact/Title").count and it always comes back as 0 for count. I am missing something obvious here. In my example above the XML document that is returned to is below: <?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><soap:Body><submitContactResponse xmlns="evententerprise"><submitContactResult><ROOT xmlns=""><Title xmlns="evententerprise">Mr</Title><GivenName xmlns="evententerprise">Andi</GivenName><MiddleName xmlns="evententerprise">Thornton</MiddleName><Surname xmlns="evententerprise">Cooper</Surname><Department xmlns="evententerprise">department</Department><Assistant xmlns="evententerprise">Assistants%20Name</Assistant><Manager xmlns="evententerprise">Managers%20Name</Manager><Profession xmlns="evententerprise">profession</Profession><JobTitle xmlns="evententerprise">Job%20Title</JobTitle><EmployeeNumber xmlns="evententerprise">employee%20number</EmployeeNumber><Company xmlns="evententerprise">Company</Company><Language xmlns="evententerprise">English</Language><email1 xmlns="evententerprise">andic@magma.ca</email1><email2 xmlns="evententerprise">email2@hotmail.com</email2><email3 xmlns="evententerprise">email3@hotmail.com</email3><email xmlns="evententerprise">email1</email><webpage xmlns="evententerprise">http://web%20page%20address</webpage><BusinessPhone xmlns="evententerprise">business%20phone</BusinessPhone><HomePhone xmlns="evententerprise">home%20phone</HomePhone><BusinessFax xmlns="evententerprise">bus%20fax</BusinessFax><Mobile xmlns="evententerprise">mobile</Mobile><Street xmlns="evententerprise">street%20name</Street><City xmlns="evententerprise">city</City><State xmlns="evententerprise">state</State><PostalCode xmlns="evententerprise">postal</PostalCode><Country xmlns="evententerprise">country</Country></ROOT></submitContactResult></submitContactResponse></soap:Body></soap:Envelope> If have also tried doing the following : nsmgr.AddNamespace("xsd", "http://www.w3.org/2001/XMLSchema") nsmgr.AddNamespace("soap", "http://schemas.xmlsoap.org/soap/envelope/") nsmgr.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance") nsmgr.AddNamespace("", "evententerprise") I am missing something but just can't figure it the hell out!!! Hi Keith, Remember, that everything outside of the Body element in the soap envelope will not be passed to the method (this is why you get an XMLNode and not an XML document). You shouldn't have to do a loadXMl at all, since the serialization to an XmlNode is already finished at this point. Here are some questions: 1. Is the XmlNode member named Data non-null when the method is invoked? 2. If it is non-null, it is an XMlNode and you can use it as an object reference. The next question is what line of code is throwing the uninitialized object exception? I suspect it is when you try to use the node reference that can be returned by selectSingleNode. Remember, if SelectSingleNode doesn't find anything, it returns null. Adding namespaces won't do much for you since this isn't a namespace issue. From the data you see coming back from your <ROOT> experiment, it seems that the original request data is making it into your method just fine. The non-namespace on your concatenated root node is what is making all of those added child namespace markup appear - so again, the serializer seems to be doing it's job correctly. What is left to conclude then is that the Xpath expression is saying that no results are found. You need to accommodate namespace in your xpath queries - so I suspect your test is looking for Test in the non-namespace, when your data is namespaced. I hope this helps Dan Rogers Microsoft Corporation -------------------- >From: "Keith Chadwick" <webmaster-nospam@allianceevents.com> >References: <#qG4gTl1EHA.3500@TK2MSFTNGP09.phx.gbl> <bfe1rkl1EHA.3388@cpmsftngxa10.phx.gbl> >Subject: Re: PLEASE HELP - object reference not set to instance of an object >Date: Mon, 29 Nov 2004 16:31:04 -0500 >Lines: 70 [quoted text clipped - 7 lines] >NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >Path: cpmsftngxa10.phx.gbl!TK2MSFTNGXS01.phx.gbl!cpmsftngxa06.phx.gbl!TK2MSFTNGP08 .phx.gbl!TK2MSFTNGP15.phx.gbl >Xref: cpmsftngxa10.phx.gbl microsoft.public.dotnet.framework.aspnet.webservices:26878 >X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webservices > [quoted text clipped - 65 lines] > >I am missing something but just can't figure it the hell out!!! Yes I came to the exact same conclusion Dan, my problem was the namespace. In my SOAP envelop it indicates xmlns="evententerprise" on the method element. This xmlns is then being passed down to the child contact item so my resulting xml in the node is: <contact address="asdfasdfasdf" xmlns="evententerprise"> <Title>something</Title> ... </contact> You are correct when I do myelement=nodeset.selectSingleNode("//Title") then try an reference myelement I get the object is not an instance because the original select single node did not return a node. So three points. 1) I am trying to get around even using namespaces as they do not provide me anything beneficial at this point, but this concerns as they may in the future. 2) Why does the Soap packet pass the xmlns namespace down to the root node of the data variable that is passed and can I stop it from doing this? 3) Deal with the namespace issue and figure out how to work with it :-) The learning curve goes on! Cheers Keith > Hi Keith, > [quoted text clipped - 123 lines] >> >>I am missing something but just can't figure it the hell out!!! Hi Keith, Namespace is an intrinsic part of XML. You could opt (for expedience sake) to place the XML nodes in the non-namespace by passing an empty string when you do the first CreateNode() via the DOM (assuming this is the case). But the easiest thing to do, if you ask me, is to get good at dealing with namespace now if you continue to deal with raw XML. Namespace adds the added contextual information that lets someone know they have YOUR data type and intended definitions, instead of relying on the name of the element alone. Try to not think of the XML on the wire as a string that you are manipulating - it's more than that and just looks like strings. All modern (and well done) XML processors intrinsically differentiate namespace, as do all well done XSLT and XPath processors. I think you'll find an overload on selectSingleNode and SelectNodes that let you specify what namespace you wish to find. The answer to "Preventing your elements from being expressed in any given namespace" requires that I know how exactly you are creating your XML nodes. Myself, I always just deal with strong typed classes and use the XmlRootAttribute, XmlElementAttribute and XmlAttributeAttribute to do fine control over what specific atom names and namespaces appear on the wire, and have not had to hand sling DOM code since the BizTalk Jumpstart Kit tools back in 99. Dan -------------------- >From: "Keith Chadwick" <webmaster-nospam@allianceevents.com> >References: <#qG4gTl1EHA.3500@TK2MSFTNGP09.phx.gbl> <bfe1rkl1EHA.3388@cpmsftngxa10.phx.gbl> <e$LqSul1EHA.1740@TK2MSFTNGP15.phx.gbl> <FlpNxbn1EHA.3980@cpmsftngxa10.phx.gbl> >Subject: Re: PLEASE HELP - object reference not set to instance of an object >Date: Mon, 29 Nov 2004 20:56:22 -0500 >Lines: 165 [quoted text clipped - 7 lines] >NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >Path: cpmsftngxa10.phx.gbl!TK2MSFTFEED01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP14 .phx.gbl >Xref: cpmsftngxa10.phx.gbl microsoft.public.dotnet.framework.aspnet.webservices:26887 >X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webservices > [quoted text clipped - 75 lines] >>>NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >>>Path: cpmsftngxa10.phx.gbl!TK2MSFTNGXS01.phx.gbl!cpmsftngxa06.phx.gbl!TK2MSFTNGP08 >> phx.gbl!TK2MSFTNGP15.phx.gbl >>>Xref: cpmsftngxa10.phx.gbl [quoted text clipped - 72 lines] >>> >>>I am missing something but just can't figure it the hell out!!! Hey Dan, Yes I discovered that namespace was an intrinsic part of at least webservices and soap when I tried to cheat and get around it, thats how one learns. I have managed to get everything going and like anything else it is just a learning curve. Been using MSXML for years now so getting my head out of that and into .NET Xml objects is a bit of strain. What makes it harder is that my client side stuff is still using MSXML so jumping back and forth realy starts to wear the cranium down. Same sort of situation as when you spend all day writing JScript then go and write some VB.NET and keep forgetting that there is a then on the if, you start to get a little aggravated. I managed to work with the namespaces after finding an example that actualy stated that when you do AddNamespace on the namespaceManager that your xml does not have to have the namespace already declared on the element just the xmlns declared at either the element or parent node level. It seems obvious now but when you do not know, it seems completely backwards when you think about it. It's similar to doing a modify table script to add a column in sql but selecting from the column before you ran the script, if you know what I mean. I have taken on a herculean product development from home and decided to do it in .NET after spending 7 years doing ASP and SQL. You have to learn the new technology at some point given the job market. Guess my old brain just doesn't learn as quick as it did when I was a young sprig :-) Thanks for you help Dan, really appreciated. Cheers Keith > Hi Keith, > [quoted text clipped - 217 lines] >>>> >>>>I am missing something but just can't figure it the hell out!!! Hi Kieth, Great. Yes, there is a learning curve. There are some short-cuts though - and giving up half of the hand coding was a blessing for me. If you already have a schema for your on the wire body-payloads, try running them through XsdObjectGen.exe (download it from Microsoft.Com/Downloads - keyword is XsdObjectGen.exe) - it'll build most of the data management classes for you automatically, so you don't have to have as-long a learning curve. We built it to help me code this same kind of app faster and more reliably. Glad to help where I can Dan -------------------- >From: "Keith Chadwick" <webmaster-nospam@allianceevents.com> >References: <#qG4gTl1EHA.3500@TK2MSFTNGP09.phx.gbl> <bfe1rkl1EHA.3388@cpmsftngxa10.phx.gbl> <e$LqSul1EHA.1740@TK2MSFTNGP15.phx.gbl> <FlpNxbn1EHA.3980@cpmsftngxa10.phx.gbl> <ORjJiCo1EHA.1300@TK2MSFTNGP14.phx.gbl> <y7kqPPy1EHA.3956@cpmsftngxa10.phx.gbl> >Subject: Re: PLEASE HELP - object reference not set to instance of an object >Date: Tue, 30 Nov 2004 17:27:45 -0500 >Lines: 273 [quoted text clipped - 7 lines] >NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >Path: cpmsftngxa10.phx.gbl!TK2MSFTFEED02.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP14 .phx.gbl >Xref: cpmsftngxa10.phx.gbl microsoft.public.dotnet.framework.aspnet.webservices:26907 >X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webservices > [quoted text clipped - 80 lines] >>>NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >>>Path: cpmsftngxa10.phx.gbl!TK2MSFTFEED01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP14 >> phx.gbl >>>Xref: cpmsftngxa10.phx.gbl [quoted text clipped - 87 lines] >>>>>NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >>>>>Path: cpmsftngxa10.phx.gbl!TK2MSFTNGXS01.phx.gbl!cpmsftngxa06.phx.gbl!TK2MSFTNGP08 >>>> phx.gbl!TK2MSFTNGP15.phx.gbl >>>>>Xref: cpmsftngxa10.phx.gbl [quoted text clipped - 75 lines] >>>>> >>>>>I am missing something but just can't figure it the hell out!!! The brains been working on namespace so I have a question . On of the key things I would like to make available through this system is for third party developers to use the webservices to retrieve and send information back and forth over the wire. Basically we would act as a place to store there data. To do this there should be a schema available that they can point to in order to understand the information they are receiving. For instance <?xml?> <root xmlns:eve="http://www.mydomain.com/schema"> <eve:something> .... </eve:something> </root> When the above xml is parsed the actual schema is downloaded and used by the parser to understand the xml. Am I right so far? Now with regards to web services should the web service point to the same schema as in <system.web.services.webserver(Namespace:="http://www.mydomain.com/schema"> or is this something entirely different. I am not sure how the two would link together? You will have to forgive my naivet? but I have been avoiding schemas like the plague for two years now :-) Cheers Keith > Hi Keith, > [quoted text clipped - 217 lines] >>>> >>>>I am missing something but just can't figure it the hell out!!! Hi Kieth, Actually, there is a very formal schema definition language at this point, and it is an integral part of the web service programming stack. Once you have built an ASP.net web service that is returning full fledged types (and not XmlNodes), you will be able to see the schema and WSDL (web service description language) standard format (kind of like IDL for web services) by typing http://myservicehost/myserviceproject/myservice.aspx?WSDL in your browser command line. This is what is used by the add-web-reference proxy generation tool in VS.net (which in turn calls into WSDL.exe to generate the code for the proxy). That WSDL will contain the schemas required, or references to the schemas if you get into the more complex, well versioned cases at a later date. If you start out with classes that are just plain classes you design and code, you will get your schemas for free. An easy learning curve! Hope this helps Dan Rogers Microsoft Corporation -------------------- >From: "Keith Chadwick" <webmaster-nospam@allianceevents.com> >References: <#qG4gTl1EHA.3500@TK2MSFTNGP09.phx.gbl> <bfe1rkl1EHA.3388@cpmsftngxa10.phx.gbl> <e$LqSul1EHA.1740@TK2MSFTNGP15.phx.gbl> <FlpNxbn1EHA.3980@cpmsftngxa10.phx.gbl> <ORjJiCo1EHA.1300@TK2MSFTNGP14.phx.gbl> <y7kqPPy1EHA.3956@cpmsftngxa10.phx.gbl> >Subject: Re: PLEASE HELP - object reference not set to instance of an object >Date: Tue, 30 Nov 2004 17:50:50 -0500 >Lines: 274 [quoted text clipped - 7 lines] >NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >Path: cpmsftngxa10.phx.gbl!TK2MSFTFEED02.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP11 .phx.gbl >Xref: cpmsftngxa10.phx.gbl microsoft.public.dotnet.framework.aspnet.webservices:26909 >X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webservices > [quoted text clipped - 80 lines] >>>NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >>>Path: cpmsftngxa10.phx.gbl!TK2MSFTFEED01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP14 >> phx.gbl >>>Xref: cpmsftngxa10.phx.gbl [quoted text clipped - 87 lines] >>>>>NNTP-Posting-Host: ottawa-hs-64-26-156-220.s-ip.magma.ca 64.26.156.220 >>>>>Path: cpmsftngxa10.phx.gbl!TK2MSFTNGXS01.phx.gbl!cpmsftngxa06.phx.gbl!TK2MSFTNGP08 >>>> phx.gbl!TK2MSFTNGP15.phx.gbl >>>>>Xref: cpmsftngxa10.phx.gbl [quoted text clipped - 75 lines] >>>>> >>>>>I am missing something but just can't figure it the hell out!!! Thanks Dan, the light buld just go a lot brighter. Of course if I type my services instead of sending a xml 'blob' down to one service then the WDSL of the service already acts as a schema to fully describe it. Now things are becomming a lot clearer. I try to leverage xml and schemas client side in order to prevent submissions of data that is invalid. In many cases I do the same validation again server side. So I guess I can simply use the WDSL of the service. Thanks very much starting to see the bigger picture now and how things integrate. Think I was still thinking to much along the lines of old asp where we would leveral xml to do this stuff for us. Always got nervous when the manufacturer said they did it for me, always ended up painting myself into a corner :-) Cheers Keith > Hi Kieth, > [quoted text clipped - 328 lines] >>>>>> >>>>>>I am missing something but just can't figure it the hell out!!! Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
|
Reply to this Message
|
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.