WCF service. Exception: formatting throws an exception when trying to deserialize a message

Question

When trying to deserialize the message, the formatter threw an exception:

An error occurred while trying to deserialize the parameter http://tempuri.org/:GetPatientInsuranceInformationResult . The InnerException message was "Error on line 1 of position 1604. The element ' http://schemas.datacontract.org/2004/07/SubSonic:_currentValue ' contains data ' http://schemas.datacontract.org/2004/07/System: DBNull is a data contract. Deserializer does not know any type that matches this contract. Add the type corresponding to "DBNull" to the list of known types - for example, using the KnownTypeAttribute attribute or adding it to the list of known types passed to the DataContractSerializer. " . See InnerException for more details.

my utility function wcf

public PatientInsurance GetPatientInsuranceInformation(int PatientKey)
        {
            PatientInsurance col = new PatientInsurance();
            if (PatientKey > 0)
            {
                Query qry = new Query(PatientInsurance.Schema.TableName).WHERE(PatientInsurance.Columns.Deleted, false).AND(PatientInsurance.Columns.PatientKey, PatientKey);
                col.LoadAndCloseReader(qry.ExecuteReader());
            }
            return col;
        }

. -

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Serialization;


namespace PatientPortal.Model.Data
{
    [KnownType(typeof(System.DBNull))]
    [XmlInclude(typeof(DBNull))]
    [KnownType(typeof(PatientInsurance))]
    public partial class PatientInsurance
    {
        public string InsuranceTypeText
        {
            get
            {
                string insuranceTypeText = "";
                //if (!string.IsNullOrEmpty(Convert.ToString(this.InsuranceType)))
                //{
                //    int InsuranceType = Convert.ToInt32(this.InsuranceType);
                //    switch (InsuranceType)
                //    {
                //        case 1:
                //            insuranceTypeText = "Primary Insurance";
                //            break;
                //        case 2:
                //            insuranceTypeText = "Secondary Insurance";
                //            break;
                //        case 3:
                //            insuranceTypeText = "Tertiary Insurance";
                //            break;
                //    }
                //}
                return insuranceTypeText;
            }
        }

        public string PrimPolicyHolderNameDisplay
        {
            get
            {
                string primPolicyHolderNameDisplay = "display:none;";
                if (!string.IsNullOrEmpty(Convert.ToString(this.PrimRelationship)))
                {
                    primPolicyHolderNameDisplay = (this.PrimRelationship == "Self") ? "display:none;" : "";
                }
                return primPolicyHolderNameDisplay;
            }
        }

        public string SecPolicyHolderNameDisplay
        {
            get
            {
                string secPolicyHolderNameDisplay = "display:none;";
                if (!string.IsNullOrEmpty(Convert.ToString(this.SecRelationship)))
                {
                    secPolicyHolderNameDisplay = (this.SecRelationship == "Self") ? "display:none;" : "";
                }
                return secPolicyHolderNameDisplay;
            }
        }

        public string TerPolicyHolderNameDisplay
        {
            get
            {
                string terPolicyHolderNameDisplay = "display:none;";
                if (!string.IsNullOrEmpty(Convert.ToString(this.TerRelationship)))
                {
                    terPolicyHolderNameDisplay = (this.TerRelationship == "Self") ? "display:none;" : "";
                }
                return terPolicyHolderNameDisplay;
            }
        }
    }
}

.

Answer 1

WCF 4.5, - 3.5. - Class KnownTypes,

 [ServiceKnownType(typeof(System.DBNull))] 

, System.DBNull. .

, :

<system.runtime.serialization>
        <dataContractSerializer>    
            <declaredTypes>
                <add type="NameSpace.ServiceClientName.ClassNameForWhichKnownTypeIsToBeGiven, AssemblyName">
                    <knownType  type="System.DBNull"></knownType>
                </add>
             </declaredTypes>
        </dataContractSerializer>
</system.runtime.serialization> 

Answer 2

, DBNull. Deserializer WCF , , . KnownTypeAttribute DBNull, .

:

[CollectionDataContract]
[KnownType(typeof(DBNull))]
public class YourList : ArrayList {
}