将返回类型转换为数组C＃

Question

I have a method that ts returning Array. I have problem with one class that cant convert the return type to array.

This is my method:

      public Model.BaseType[] returnPayment_Gateway()
    {
        IncomingWebRequestContext request = WebOperationContext.Current.IncomingRequest;
        WebHeaderCollection headers = request.Headers;
        var settings = new DataContractJsonSerializerSettings { EmitTypeInformation = EmitTypeInformation.Never };

        MemoryStream stream1 = new MemoryStream();

        DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Model.BaseType),settings);

        Model.Payment_Gateway[] allRecords = null;


        if (headers["ServiceAuthentication"] != null)
        {
         string   ServiceAuthentication = headers["ServiceAuthentication"].ToString();
          bool  serviceAuth = Service_Authentication(ServiceAuthentication);

          DAL.DataManager dal = new DAL.DataManager();

            if (serviceAuth == true)
            {
               allRecords = dal.Get_Payment_Gateway();

            }
        }

        else
        {


               // Create a new customer to return


            return new Model.ReturnResponse() { StatusCode = 201, StatusDescription = "Authentication Fails" };


        }

        return allRecords;
    }

My problem is in else part, not sure how I can convert Model.ReturnResponse() to array now I am getting this error:

cannot implicitly convert type ReturnResponse to Model.BaseType[]

in case you like to see my 3 classes:

This is Base class:

[Serializable]
[DataContract]
[KnownType(typeof(Payment_Gateway))]
[KnownType(typeof(ReturnResponse))]

public class BaseType 
{

}

this is Payment_Gateway class:

[DataContract]
public class Payment_Gateway:BaseType
{
    [DataMember]
    public int Payment_Gateway_ID { get; set; }

    [DataMember]
    public string Payment_Gateway_Name { get; set; }

    [DataMember]
    public string Payment_Gateway_URL { get; set; }

    [DataMember]
    public string Payment_Gateway_Description { get; set; }

and this is ReturnResponse class:

[DataContract]
public class ReturnResponse:BaseType
{
    [DataMember]
    public int StatusCode { get; set; }

    [DataMember]
    public string StatusDescription { get; set; }


}

Answer 1

Instead of trying to return a single ReturnResponse :

return new Model.ReturnResponse()
    { StatusCode = 201, StatusDescription = "Authentication Fails" };

Return an array, with the single element in it, since that's what your method is expected to return:

return new[] {
    new Model.ReturnResponse()
        { StatusCode = 201, StatusDescription = "Authentication Fails" }
    }

Answer 2

Instead of the hierarchy you have designed here, it would be easier if you encapsulate your return data in a response object that indicate a response type (success or failure) and the resulting data.

that class could look like the following

public enum ResponseTypes
{
    Success,
    Failure
}

public class Response
{
    public ResponseTypes ResponseType {get; set;}
    public Exception Error {get;set;}
    public BaseType[] Data {get;set;}
}

this way it works like an envelope to your actual data and provides state to the caller to know if the call succeeded or not, and maybe for what reason, before reading the data (result)

its the same way WCF acts under the hood (in SOAP, at least) that it surrounds your data contract with a message envelope/enclosure to add more metadata for the caller to interpret the call status.