I am trying to return an object of my class Product as Json for a webservice. The object is loaded with all the values but I get an error when it attempts to return it as Json. Here is my method:
<AllowAnonymous> <HttpGet> _
Public Function GetProduct() As HttpResponseMessage
Try
Dim oProduct As New Product
oProduct = Product.GetProductByID(25)
Dim jsSerializer As System.Web.Script.Serialization.JavaScriptSerializer
jsSerializer = New System.Web.Script.Serialization.JavaScriptSerializer()
Dim sbProduct As New System.Text.StringBuilder()
jsSerializer.Serialize(oProduct, sbProduct)
Dim json As String = sbProduct.ToString()
Return Request.CreateResponse(HttpStatusCode.OK, json)
Catch exc As Exception
Return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, exc)
End Try
End Function
The response:
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<Error>
<Message>An error has occurred.</Message>
<ExceptionMessage>
Exception has been thrown by the target of an invocation.
</ExceptionMessage>
<ExceptionType>System.Reflection.TargetInvocationException</ExceptionType>
<StackTrace>
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.Web.SecurityUtils.MethodInfoInvoke(MethodInfo method, Object target, Object[] args) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj, StringBuilder output, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj, StringBuilder output) at Christoc.Modules.top3all.ModuleTaskController.GetProduct() in C:\inetpub\wwwroot\top3\DesktopModules\top3all\Models\WebServices.vb:line 30
</StackTrace>
<InnerException>
<Message>An error has occurred.</Message>
<ExceptionMessage>
Object reference not set to an instance of an object.
</ExceptionMessage>
<ExceptionType>System.NullReferenceException</ExceptionType>
<StackTrace>
at DotNetNuke.Security.Permissions.PermissionProvider.HasModuleAccess(SecurityAccessLevel accessLevel, String permissionKey, ModuleInfo moduleConfiguration) at DotNetNuke.Security.Permissions.ModulePermissionController.HasModuleAccess(SecurityAccessLevel accessLevel, String permissionKey, ModuleInfo moduleConfiguration) at DotNetNuke.UI.Modules.ModuleInstanceContext.LoadActions(HttpRequest request) at DotNetNuke.UI.Modules.ModuleInstanceContext.get_Actions() at DotNetNuke.Entities.Modules.PortalModuleBase.get_Actions()
</StackTrace>
</InnerException>
</Error>
Edit #1 Definition of Product
Public Class Product Inherits AddNew
Public Shared selectedProduct As New Product
Private iProductID As Integer
Public Property ProductID() As Integer
Get
Return iProductID
End Get
Set(ByVal value As Integer)
iProductID = value
End Set
End Property
Private iCategoryID As Integer
Public Property CategoryID() As Integer
Get
Return iCategoryID
End Get
Set(ByVal value As Integer)
If IsNothing(value) Or IsDBNull(value) Then
iCategoryID = 0
Else
iCategoryID = value
End If
End Set
End Property
Private iSubCategoryID As Integer
Public Property SubCategoryID() As Integer
Get
Return iSubCategoryID
End Get
Set(ByVal value As Integer)
If IsNothing(value) Or IsDBNull(value) Then
iSubCategoryID = 0
Else
iSubCategoryID = value
End If
End Set
End Property
Private sName As String
Public Property Name() As String
Get
Return sName
End Get
Set(ByVal value As String)
sName = value
End Set
End Property
Private sDescription As String
Public Property Description() As String
Get
Return sDescription
End Get
Set(ByVal value As String)
sDescription = value
End Set
End Property
Private dPrice As Double
Public Property Price() As Double
Get
Return dPrice
End Get
Set(ByVal value As Double)
If IsNothing(value) Or IsDBNull(value) Then
dPrice = 0.0
Else
dPrice = value
End If
End Set
End Property
Private sCurrencyCulture As String
Public Property CurrencyCulture() As String
Get
Return sCurrencyCulture
End Get
Set(ByVal value As String)
sCurrencyCulture = value
End Set
End Property
Private sKeywords As String
Public Property Keywords() As String
Get
Return sKeywords
End Get
Set(ByVal value As String)
sKeywords = value
End Set
End Property
Private sCountry As String
Public Property Country() As String
Get
Return sCountry
End Get
Set(ByVal value As String)
sCountry = value
End Set
End Property
Private iViews As Integer
Public Property Views() As Integer
Get
Return iViews
End Get
Set(ByVal value As Integer)
If IsNothing(value) Or IsDBNull(value) Then
iViews = 0
Else
iViews = value
End If
End Set
End Property
Private iRating As Integer
Public Property Rating() As Integer
Get
Return iRating
End Get
Set(ByVal value As Integer)
If IsNothing(value) Or IsDBNull(value) Then
iRating = 0.0
Else
iRating = value
End If
End Set
End Property
Private dDateAdded As DateTime
Public Property DateAdded() As DateTime
Get
Return dDateAdded
End Get
Set(ByVal value As DateTime)
dDateAdded = value
End Set
End Property
Private sAffiliateLink As String
Public Property AffiliateLink() As String
Get
Return sAffiliateLink
End Get
Set(ByVal value As String)
sAffiliateLink = value
End Set
End Property
Private sAffiliateID As String
Public Property AffiliateID() As String
Get
Return sAffiliateID
End Get
Set(ByVal value As String)
sAffiliateID = value
End Set
End Property
Private iAddedBy As Integer
Public Property AddedBy() As Integer
Get
Return iAddedBy
End Get
Set(ByVal value As Integer)
iAddedBy = value
End Set
End Property
Private iImage As Integer
Public Property Image() As Integer
Get
Return iImage
End Get
Set(ByVal value As Integer)
iImage = value
End Set
End Property
Private iThumbnail As Integer
Public Property Thumbnail() As Integer
Get
Return iThumbnail
End Get
Set(ByVal value As Integer)
iThumbnail = value
End Set
End Property
Private iModifiedBy As Integer
Public Property ModifiedBy() As Integer
Get
Return iModifiedBy
End Get
Set(ByVal value As Integer)
iModifiedBy = value
End Set
End Property
Private dtModifiedTimeUtc As DateTime
Public Property ModifiedTimeUtc() As DateTime
Get
Return dtModifiedTimeUtc
End Get
Set(ByVal value As DateTime)
dtModifiedTimeUtc = value
End Set
End Property
Private sSource As String
Public Property Source() As String
Get
Return sSource
End Get
Set(ByVal value As String)
sSource = value
End Set
End Property
Private iModuleID As Integer
Public Property ModID() As Integer
Get
Return iModuleID
End Get
Set(ByVal value As Integer)
iModuleID = value
End Set
End Property
Private iPortalID As Integer
Public Property PortID() As Integer
Get
Return iPortalID
End Get
Set(ByVal value As Integer)
iPortalID = value
End Set
End Property
Any ideas how to fix this?
Some member in Product or in the inheritance chain is probably uninitialized. This can be easy to miss, especially in VB.NET.
Collected from the Internet
Please contact [email protected] to delete if infringement.
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