WCF client side List<> - wcf

I got a WCF service with a method (GetUserSoftware)to send a List to a client.
the software I have defined like this:
[DataContract]
public class Software
{
public string SoftwareID { get; set; }
public string SoftwareName { get; set; }
public string DownloadPath { get; set; }
public int PackageID { get; set; }
}
the method is going through my db to get all software availeble to the clien, and generates a list of that to send back to the client.
problem is i on the client side the list is turned into an array. and every item in that array dont contain any of my software attributs.
i have debugged my way through the server side. and seen that the list its about to send is correct. with the expected software and attributs in it.
any one know how to work around this or know what i can do ?

Did you forget [DataMemeber] attribute on your properties?

When you use DataContract attribute for a type you have to use DataMember attribute for each property or field you want to serialize and transfer between service and client. Collections are by default created as arrays. If you don't like it you can change this behavior in Add Service Reference window -> Advanced settings where you can select which collection type should be used.

First off, each of the properties that you want to serialize should have the [DataMember] attribute:
[DataContract]
public class Software
{
[DataMember]
public string SoftwareID { get; set; }
[DataMember]
public string SoftwareName { get; set; }
[DataMember]
public string DownloadPath { get; set; }
[DataMember]
public int PackageID { get; set; }
}
Second, the translation to an Array would be handled by the client, not the server.

You can mantain List instead of array on the clien when you add the Service Reference: click the "advanced" button and change the collection type to the one you want.

I was suffering with same problem and now I solved it! It was a ServiceKnownType problem. If you have a in known type loader we have to add runtime Type like;
Type aaa = Type.GetType("System.Collections.Generic.List`1[[ProjectName.BusinessObjects.Bank, ProjectName.BusinessObjects, Version=4.0.0.0, Culture=neutral, PublicKeyToken=null]]");
knownTypes.Add(aaa);
Anyone having same problem can try this. It's working in my environment!

Related

Confused about DTOs when reading and editing. How to desing DTO for filling the form in VUEjs app?

I am trying to develop an enterprise-level application. I have domain and application services. I have created my DTOs for multiple purposes separately. But confused about which way I should use them from the API viewpoint.
I have complex objects lets say,
public class Entity{
public int Id { get; set; }
public string Name { get; set; }
public int? ManufacturerId { get; set; }
public virtual Manufacturer Manufacturer { get; set; }
}
public class Manufacturer{
public int Id { get; set; }
public string Text { get; set; }
}
And I have corresponding DTOs designed with composition now. It was separated before.
public class EntityBaseDto{
public string Name { get; set; }
}
public class EntityReadDto : EntityBaseDto{
public string Manufacturer { get; set; }
}
public class EntityWriteDto : EntityBaseDto{
public int? ManufacturerId { get; set; }
}
Now the question is,
I have a table which is filled with List<EntityReadDto> which is clear. Before, EntityReadDto also had the ManufacturerDto as fully included with id and text. Whenever I require to edit one of the entries from the table I was able to load the dropdown selected items or list of tags etc with the ids attached to the Manufacturer objects within ReadDtos. Now it is not possible. Since I wanted to simplify the codes I just converted them to strings that are read-only. Now I have created another endpoint to get an editable version of the record when needed. Ex: EntityWriteDto will be used to fill the form when the edit is clicked on a specific item. The manipulation will be carried on that DTO and sent with the PUT type request to edit the record.
I am not sure if this approach is ok for these cases. What is the best practice for this? I have many objects related to the entities from other tables. Is it ok to make a call to get an editable version from the backend or need to have it right away in a VUEjs app?

why WCF service don't return list<>?

When i add/edit the service client, if i click on the "Advanced ..." button i will see an option allowing me to choose the collection type for my client proxy . The default is System.Array. When I change to System.Collaction.Generic.List and click Add proxy create. But in my method return value i see type[] but not List, why? What i do wrong?
this is class:
[DataContract]
public class Asset
{
[DataMember]
public decimal AssetId { get; set; }
[DataMember]
public string AssetName { get; set; }
}
when you generate proxy class choise List instead Array

.NET WebAPI Serialization k_BackingField Nastiness

When i serialize the following:
[Serializable]
public class Error
{
public string Status { get; set; }
public string Message { get; set; }
public string ErrorReferenceCode { get; set; }
public List<FriendlyError> Errors { get; set; }
}
I get this disgusting mess:
<ErrorRootOfstring xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/Printmee.Api">
<_x003C_Errors_x003E_k__BackingField>
An exception has occurred. Please contact printmee support
</_x003C_Errors_x003E_k__BackingField>
<_x003C_LookupCode_x003E_k__BackingField>988232ec-6bc9-48f3-8116-7ff7c71302dd</_x003C_LookupCode_x003E_k__BackingField>
</ErrorRootOfstring>
What gives? How can i make this pretty? JSON responses also contain the k_BackingField
By default you don't need to use neither [Serializable] nor [DataContract] to work with Web API.
Just leave your model as is, and Web API would serialize all the public properties for you.
Only if you want to have more control about what's included, you then decorate your class with [DataContract] and the properties to be included with [DataMember] (because both DCS and JSON.NET respsect these attributes).
If for some reason, you need the [Serializable] on your class (i.e. you are serializing it into a memory stream for some reason, doing deep copies etc), then you have to use both attributes in conjunction to prevent the backing field names:
[Serializable]
[DataContract]
public class Error
{
[DataMember]
public string Status { get; set; }
[DataMember]
public string Message { get; set; }
[DataMember]
public string ErrorReferenceCode { get; set; }
[DataMember]
public List<FriendlyError> Errors { get; set; }
}
There is a more general solution: you can configure the Json Serializer to ignore the [Serializable] attribute, so that you don't have to change the attributes in your classes.
You should make this configuration change in the application start, i.e. in Global.asax Application_Start event:
var serializerSettings =
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings;
var contractResolver =
(DefaultContractResolver)serializerSettings.ContractResolver;
contractResolver.IgnoreSerializableAttribute = true;
You can also make other changes to the Json serialization, like specifying formats for serializing dates, and many other things.
This will only apply to the Web API JSON serialization. The other serializations in the app (Web API XML serialization, MVC JsonResult...) won't be affected by this setting.
Try using DataContract instead of Serializable for marking your class. For more detail on why, look at this good blog post on serializing automatic properties.
The [DataContract] attributes dosn't worked for me, so it was not an option.
XmlSerializer ignores [XmlAttribute] in WebApi
The above resolution solved it for me.
GlobalConfiguration.Configuration.Formatters.XmlFormatter.UseXmlSerializer = true;

Any collection causes silent failure with 500 status code in Asp.Net MVC 4 RC Web API

I'm completely lost on what could be causing this.
I have an ASP.Net MVC 4 RC application and I have a set of Web API controllers. I'm trying to return an object that contains a set of child objects in an IList. Whenever I request the object I get a 500 error back on the browser with no noticeable exception thrown in the debugger. I've tried putting an Application_Error handler in the global.asax and no error is caught there either.
It doesn't matter whether the List is an actual database relation or just a hard coded list of strings, in either case the request fails. If i set the list to null the request succeeds.
If i remove the list the request succeeds and I get an XML (or JSON) representation of the object.
I've also tried this line -
GlobalConfiguration.Configuration.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;
To capture the actual exception and still get nothing back.
Here's the current object
public class Authority : IEntity
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual string Address1 { get; set; }
public virtual string Address2 { get; set; }
public virtual string City { get; set; }
public virtual string County { get; set; }
public virtual string State { get; set; }
public virtual string ContactPostalCode { get; set; }
//public virtual IList<PostalCode> PostalCodes { get; set; }
public virtual IList<string> RandomTrash { get; set; }
public VPA()
{
//PostalCodes = new List<PostalCode>();
RandomTrash = new List<string> {"foo"};
}
}
Note the commented out PostalCodes collection - that is a real many to many database relationship. I commented it out and replaced it with the dummy "RandomTrash" collection and the failure seems to be the same.
I have a feeling this is a serialization failure somehow but I can't figure out how to avoid it. If it helps I'm using NHibernate as the ORM.
Has anyone seen this?
Answering my own question in case anyone runs into this again.
It ended up being Serialization following the grid in a loop. To fix i added 2 attributes to each looping reference in one of the models.
[IgnoreDataMember] For the XML Serializer
[JsonIgnore] For JSON.Net's Serializer.
I added those the PostalCode class on the IList property.
There may be a better solution. The downside of this one is it makes my API one sided. I can request an Authority and get all of it's postal codes, but i can't request a postal code and get all of it's Authorities.

Adding dynamic datamembers to DataContract

I have WCF service that return Json.
Data contract defined below
[DataContract]
public class OptionData
{
[DataMember]
public string Book { get; set; }
[DataMember]
public string Id { get; set; }
[DataMember]
public string DealId { get; set; }
[DataMember]
public string DeliveryDate { get; set; }
[DataMember]
public string ExpiryDate { get; set; }
}
And Operation Contract defined as follows
[Description("Returns List of Options by user id")]
[WebGet(UriTemplate = "{sessionId}/Application/{applicationId}?start={start}&limit={limit}&page={page}", ResponseFormat = WebMessageFormat.Json)]
public List<OptionData> GetAllTask(string sessionId, string applicationId)
I need to add dynamically new DataMember field to the OptionData class .
What is the best practice to do it ?
As long as the client receiving the json knows how to handle dynamically added class members, you can use the Expando object strategy outlined in the accepted answer to this SO question. It uses the ServiceStack library but you may be able extract the necessary code to do what you want. A simple key/value pair approach from an ExpandoObject is documented in this code snippet.
EDIT: I should point out that this approach wouldn't rely on WCF so it may not be what you need given the context of the question.
If you know you want JSON, you could always control the serialization yourself (see this post) - just return a string of JSON using an existing library.
Another option is to just us IsRequired = false if you know all the possible field names.
The final alternative is to use the same pattern WCF uses for Forward-Compatible Contracts - just attach all unknown properties to single collection object (ExtensionData). ExtensionData is just a dictionary of key/value pairs according to this post. Unfortunately - ExtensionData is not writable directly. This would be my approach to simulate what IExtensibleDataObject is doing...
[DataContract]
public class OptionData
{
[DataMember]
public string Book { get; set; }
[DataMember]
public string Id { get; set; }
[DataMember]
public string DealId { get; set; }
[DataMember]
public string DeliveryDate { get; set; }
[DataMember]
public string ExpiryDate { get; set; }
[DataMember]
public Dictionary<string, string> Metadata { get; set;}
}
I don't think this is possible.
Let's think about what your DataContract is for a moment: it's how your service defines what it knows about - either as input or output. A client has to either find this out through meta-data exchange discovery or from a static proxy class (in a dll probably) that you provide.
If you change your contract on the fly, there's no mechanism for your service to let its clients know that the contract has changed. There's just no way to change that contract on the fly.
Even if you changed the definition of the class on the fly, including the proper attributes, etc, the client would not be able to find out about it since the contract had already previously been published.
I can't imagine what kind of mechanism would be needed to communicate changes like this on the fly with a client.
The only workaround I can think of is to have a parameter that takes in a string and allows clients to pass in XML or similar which could be just about anything. That's a pretty nasty hack though...
I just ran up against this exact issue as i posted recently here:
Configuring WCF data contract for proper JSON response
My solution was to use ExpandoObject. However, I had to use Newtsoft.json to do the JSON serialization then I had to make my webservice return raw text (rather than rely on the WCF serialization). I would be happy to post my code if you like. There may be a way to do dynamic datacontracts, but I wasn't able to figure that out. But my solution does the job.
If you need to dynamically control the data structures your RESTful service is returning, I think your only option is to return something like an XDocument. Your service operation could create an XDocument of an arbitrary structure and return that. That being said, I'm not sure what would happen when WCF tries to serialize an XDocument to JSON.