Re: Add Web Reference Error
- From: "CT" <carstent@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Sat, 24 Sep 2005 08:46:24 +0200
Ross,
You will not have this working, because the DataReader needs an open
connection when you retrieve the items in it. Once it's returned from the
Web service, the Web service forgets all about it and the connection is
closed. You should consider using the DataSet or if you're using VB 2005, a
DataTable to return the rows, as these classes are serializable.
--
Carsten Thomsen
Enterprise Development with VS .NET, UML, AND MSF
http://www.apress.com/book/bookDisplay.html?bID=105
Communities - http://community.integratedsolutions.dk
"Ross" <Ross@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:E0B626A3-C6A7-4DC1-A9E0-9593A2C28464@xxxxxxxxxxxxxxxx
> Hi folks
>
> I have a <WebMethod> public function called GetCountriesForCountryStart
> that
> has a single input parameter (Varchar 50) and returns a SQLDataReader.
>
> The relevant code is as follows:
>
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> <WebMethod()> Public Function GetCountriesForCountryStart(ByVal
> strCountryStart As String) As SqlDataReader
>
> Dim cn As SqlConnection
> Dim strInfo As String
> Dim cmd As SqlCommand
> Dim prmTemp As SqlParameter
> Dim intResult As Integer
> Dim rdCountries As SqlDataReader
>
> strInfo =
> "server=(local);uid=dbo;pwd=;database=FusionCommunityVolunteerSystem;Persist
> Security Info=False;Integrated Security=SSPI"
>
> 'open connection to DB
> Try
> cn = New SqlConnection
> cn.ConnectionString = strInfo
> cn.Open()
>
> 'no errors in opening connection, so now create command
> 'to run the SP "procCountryGetForNameStart"
> Try
>
> cmd = New SqlCommand
>
> With cmd
> .Connection = cn
> .CommandType = CommandType.StoredProcedure
> .CommandText = "procCountryGetForNameStart"
>
> prmTemp = .Parameters.Add("@namestart",
> SqlDbType.VarChar, 50)
> prmTemp.Direction = ParameterDirection.Input
> prmTemp.Value = strCountryStart
>
> 'execute the SP - this returns 2 columns - CountryID &
> CountryName
> rdCountries = .ExecuteReader()
>
> Return rdCountries
>
> End With
> Catch ex As Exception
>
> End Try
>
> Catch ex As Exception
>
> Finally
> 'check to see if connection is open & if so, then close it
> If cn.State = ConnectionState.Open Then
> cn.Close()
> End If
> End Try
> End Function
>
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> I also have a web form that has a dropdownlist box that I want to populate
> with the output from the DataReader based upon a entry in a text box on
> the
> same form.
>
> However, when I try to create a web reference from the project for the
> form
> to the project that contains the method GetCountriesForCountryStart I
> receive
> the following error:
>
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> "System.NullReferenceException: Object reference not set to an instance of
> an object"
>
> The stack trace seems to be pointing to an error in the above function &
> is
> as follows:
>
> [NullReferenceException: Object reference not set to an instance of an
> object.]
> System.Xml.Serialization.XmlAttributes..ctor(ICustomAttributeProvider
> provider) +105
> System.Xml.Serialization.TypeScope.GetEnumeratorElementType(Type type)
> +107
> System.Xml.Serialization.TypeScope.ImportTypeDesc(Type type, Boolean
> canBePrimitive, MemberInfo memberInfo) +1463
> System.Xml.Serialization.TypeScope.GetTypeDesc(Type type, MemberInfo
> source, Boolean directReference) +50
>
> System.Xml.Serialization.XmlReflectionImporter.ImportMemberMapping(XmlReflectionMember
> xmlReflectionMember, String ns, XmlReflectionMember[]
> xmlReflectionMembers)
> +34
>
> System.Xml.Serialization.XmlReflectionImporter.ImportMembersMapping(XmlReflectionMember[]
> xmlReflectionMembers, String ns, Boolean hasWrapperElement) +300
>
> [InvalidOperationException: There was an error reflecting
> 'GetCountriesForCountryStartResult'.]
>
> System.Xml.Serialization.XmlReflectionImporter.ImportMembersMapping(XmlReflectionMember[]
> xmlReflectionMembers, String ns, Boolean hasWrapperElement) +607
>
> System.Xml.Serialization.XmlReflectionImporter.ImportMembersMapping(String
> elementName, String ns, XmlReflectionMember[] members, Boolean
> hasWrapperElement) +108
>
> System.Web.Services.Protocols.SoapReflector.ImportMembersMapping(XmlReflectionImporter
> xmlImporter, SoapReflectionImporter soapImporter, Boolean
> serviceDefaultIsEncoded, Boolean rpc, SoapBindingUse use,
> SoapParameterStyle
> paramStyle, String elementName, String elementNamespace, Boolean
> nsIsDefault,
> XmlReflectionMember[] members, Boolean validate) +169
>
> System.Web.Services.Protocols.SoapReflector.ReflectMethod(LogicalMethodInfo
> methodInfo, Boolean client, XmlReflectionImporter xmlImporter,
> SoapReflectionImporter soapImporter, String defaultNs) +2927
>
> [InvalidOperationException: Method
> CountriesService.GetCountriesForCountryStart can not be reflected.]
>
> System.Web.Services.Protocols.SoapReflector.ReflectMethod(LogicalMethodInfo
> methodInfo, Boolean client, XmlReflectionImporter xmlImporter,
> SoapReflectionImporter soapImporter, String defaultNs) +5494
> System.Web.Services.Description.SoapProtocolReflector.ReflectMethod()
> +130
>
> System.Web.Services.Description.ProtocolReflector.ReflectBinding(ReflectedBinding
> reflectedBinding) +1966
> System.Web.Services.Description.ProtocolReflector.Reflect() +509
>
> System.Web.Services.Description.ServiceDescriptionReflector.ReflectInternal(ProtocolReflector[]
> reflectors) +495
> System.Web.Services.Description.ServiceDescriptionReflector.Reflect(Type
> type, String url) +112
> System.Web.Services.Protocols.DocumentationServerType..ctor(Type type,
> String uri) +158
> System.Web.Services.Protocols.DocumentationServerProtocol.Initialize()
> +269
> System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type,
> HttpContext context, HttpRequest request, HttpResponse response, Boolean&
> abortProcessing) +106
>
> [InvalidOperationException: Unable to handle request.]
> System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type,
> HttpContext context, HttpRequest request, HttpResponse response, Boolean&
> abortProcessing) +205
>
> System.Web.Services.Protocols.WebServiceHandlerFactory.CoreGetHandler(Type
> type, HttpContext context, HttpRequest request, HttpResponse response) +82
>
> [InvalidOperationException: Failed to handle request.]
>
> System.Web.Services.Protocols.WebServiceHandlerFactory.CoreGetHandler(Type
> type, HttpContext context, HttpRequest request, HttpResponse response)
> +154
>
> System.Web.Services.Protocols.WebServiceHandlerFactory.GetHandler(HttpContext
> context, String verb, String url, String filePath) +94
> System.Web.HttpApplication.MapHttpHandler(HttpContext context, String
> requestType, String path, String pathTranslated, Boolean useAppConfig)
> +698
>
> System.Web.MapHandlerExecutionStep.System.Web.HttpApplication+IExecutionStep.Execute()
> +95
>
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> So, I was wondering if there is something fundamentally wrong with my
> whole
> approach, or just something wrong with the code for the procedure or
> something else?
>
> Kind regards
>
> Ross Petersen
.
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