Message Contract in WCF.

Data contract provide us limited control over request and response XML messages in WCF.If we want full control over request and response xml use MessageContract.

• In general user message contract only if there is a reason ti tweak the structure of soap xml message.

• If we want to include some custom data in soap header we can use message contract. Refer following example.

    [MessageContract]
    public class EmployeeRequest
    {
        [MessageHeader(Namespace="http://abc.com/empReqObj")]
        public string tokenKey { get; set; }      
    }

• Want to change the name of wrapper element in soap message use message contract.Wrapper element is nothing but the name of operation contract.In below soap request message getEmployee is a wrapper element.

<s:Body>
       <getEmoloyee xmlns="http://tempuri.org/">
             <id>1</id>
       </getEmoloyee>
</s:Body>

• Message contract attribute has following parameters .

1. IsWrapper
2. WrapperName
3. WrapperNamespace
4. ProtectionLevel

• Message header attribute is applied on property of the class that you want to include in soap header section.
• Message body attribute is applied on property of the class that you want to include in soap body section.

 [MessageContract( WrapperName="EmployeeReqObject", IsWrapped=true,  WrapperNamespace="http://abc.com/empReqObj")]
    public class EmployeeRequest
    {
        [MessageHeader(Namespace="http://abc.com/empReqObj")]
        public string tokenKey { get; set; }
        [MessageBodyMember(Namespace="http://abc.com/empReqObj")]
        public int EmployeeID { get; set; }
    }

Programming Example :

Soap request request and response messages without using message contract is as follows.

Req soap xml :

 <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
     <s:Header>
     </s:Header>
     <s:Body>
         <getEmoloyee xmlns="http://tempuri.org/">
              <id>1</id>
         </getEmoloyee>
      </s:Body>
</s:Envelope>

Response soap xml :

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Header></s:Header>
    <s:Body>
        <getEmoloyeeResponse xmlns="http://tempuri.org/">
        <getEmoloyeeResult i:type="b:FullTimeEmployee" xmlns:a="http://abc.com/employee"
         xmlns:b="http://schemas.datacontract.org/2004/07/WcfService1">
               <a:empAddress>gurgaon</a:empAddress>
               <a:empID>1</a:empID>
               <a:empName>rahul</a:empName>
               <b:HourPaid>1000</b:HourPaid>
               <b:HourWorked>8</b:HourWorked>
               </getEmoloyeeResult>
         </getEmoloyeeResponse>
     </s:Body>
</s:Envelope>









Request and response soap xml after tweaking with message contract :

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Header>
      <h:tokenKey xmlns:h="http://abc.com/empReqObj">GHR45TY56HJ</h:tokenKey>
      <ActivityId CorrelationId="e9898ec9-1a36-4d7d-b41e-85d536d8f8b2"
       xmlns="http://schemas.microsoft.com/2004/09/ServiceModel/Diagnostics">a6ff8893-293d-4476
      -8f4a-cdefb16ca5fa</ActivityId>
</s:Header>
<s:Body>
        <EmployeeReqObject xmlns="http://abc.com/empReqObj">
           <EmployeeID>1</EmployeeID>
        </EmployeeReqObject>
</s:Body>
</s:Envelope>


<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Header></s:Header>
<s:Body>
     <EmployeeInfoObject xmlns="http://abc.com/empReqObj">
        <EmployeeID>1</EmployeeID>
        <EmployeeName>rahul</EmployeeName>
        <EmployeeAddress>gurgaon</EmployeeAddress>
        <EmployeeHourPay>1000</EmployeeHourPay>
        <EmployeeHourWork>8</EmployeeHourWork>
        <EmployeeSalary>0</EmployeeSalary>
        <EmployeeType>1</EmployeeType>
     </EmployeeInfoObject>
</s:Body>
</s:Envelope>


C#  Code:


 [MessageContract( WrapperName="EmployeeReqObject", IsWrapped=true, WrapperNamespace="http://abc.com/empReqObj")]
    public class EmployeeRequest
    {
        [MessageHeader(Namespace="http://abc.com/empReqObj")]
        public string tokenKey { get; set; }
        [MessageBodyMember(Namespace="http://abc.com/empReqObj")]
        public int EmployeeID { get; set; }
    }

    [MessageContract(WrapperName = "EmployeeInfoObject", IsWrapped = true, WrapperNamespace = "http://abc.com/empReqObj")]
    public class EmployeeInfo
    {
        public EmployeeInfo()
        { }
        public EmployeeInfo(Employee emp)
        {
            this.EmployeeID = emp.empID;
            this.EmployeeName = emp.empName;
            this.EmployeeAddress = emp.empAddress;
            this.EmployeeType = emp.empType;
            if (emp.empType == 2)
                this.EmployeeSalary = ((PartTimeEmployee)emp).Salary;
            else
            {
                this.EmployeeHourPay = ((FullTimeEmployee)emp).HourPaid;
                this.EmployeeHourWork = ((FullTimeEmployee)emp).HourWorked;
            }
        }
        [MessageBodyMember(Namespace = "http://abc.com/empReqObj", Order = 1)]
        public int EmployeeID { get; set; }
        [MessageBodyMember(Namespace = "http://abc.com/empReqObj", Order = 2)]
        public string EmployeeName { get; set; }
        [MessageBodyMember(Namespace = "http://abc.com/empReqObj", Order = 3)]
        public string EmployeeAddress { get; set; }

        [MessageBodyMember(Namespace = "http://abc.com/empReqObj", Order = 3)]
        public int EmployeeSalary { get; set; }

        [MessageBodyMember(Namespace = "http://abc.com/empReqObj", Order = 3)]
        public int EmployeeHourPay { get; set; }

        [MessageBodyMember(Namespace = "http://abc.com/empReqObj", Order = 3)]
        public int EmployeeHourWork { get; set; }


        [MessageBodyMember(Namespace = "http://abc.com/empReqObj", Order = 3)]
        public int EmployeeType { get; set; }

    }
   


    //[KnownType(typeof(PartTimeEmployee))]
    //[KnownType(typeof(FullTimeEmployee))]
    [DataContract(Namespace="http://abc.com/employee")]
    public class Employee
    {
        [DataMember]
        public int empID { get; set; }
        [DataMember]
        public string empName { get; set; }
        [DataMember]
        public string empAddress { get; set; }
        [DataMember]
        public int empType { get; set; } //1 for full time and 2 for part time

    }
    public class PartTimeEmployee : Employee
    {
        public int Salary { get; set; }
    }
    public class FullTimeEmployee : Employee
    {
        public int HourWorked { get; set; }
        public int HourPaid { get; set; }
    }






IService1.cs :


 [ServiceContract]
    public interface IService1
    {

        [OperationContract]
        void saveEmoloyee(EmployeeInfo emp);
        [OperationContract]
        EmployeeInfo getEmoloyee(EmployeeRequest req);
              
        // TODO: Add your service operations here
    } 


 Service1.svc.cs :

public class Service1 : IService1
    {

        public void saveEmoloyee(EmployeeInfo emp)
        {
        //code for save here 
        }

        public EmployeeInfo getEmoloyee(EmployeeRequest req)
        {
            Employee emp = null;
            if (req.EmployeeID == 1)
            {
                emp = new FullTimeEmployee { empID = 1, empType=1, empAddress = "gurgaon", empName = "rahul", HourPaid = 1000, HourWorked = 8 };
            }
            else
            {
                emp = new PartTimeEmployee { empID = 1, empType=2, empAddress = "gurgaon", empName = "rahul", Salary = 50000 };
            }
            return new EmployeeInfo(emp);
        }
    }


ClientApplication.aspx.cs :


 protected void btn1_Click(object sender, EventArgs e)
        {
            ServiceReference1.EmployeeRequest objReq = new ServiceReference1.EmployeeRequest();
            ServiceReference1.EmployeeInfo empInfo = new ServiceReference1.EmployeeInfo();
            objReq.EmployeeID = 1;
            objReq.tokenKey = "GHR45TY56HJ";

            ServiceReference1.IService1 client = new ServiceReference1.Service1Client();
            empInfo = client.getEmoloyee(objReq);

            if (empInfo.EmployeeType == 1)
            {
                string name = empInfo.EmployeeName;
                int hourPaid = empInfo.EmployeeHourPay;
                int hourworked = empInfo.EmployeeHourWork;
            }
            else
            {
                int salary = empInfo.EmployeeSalary;
            }
           
        }




Related Post :

Different-option-of-hosting-wcf-service
Binding-in-wcf-choosing-right-wcf
Exchanging-metadata-in-wcf
Some-interesting-facts-about-data-contract
Knowntype-attribute-in-wcf
Associating-knowntype-in-wcf
Message-contract-in-wcf
Exception-handling-in-wcf
Exception Handling in WCF - SOAP Fault in WCF
Exception Handling in WCF - Unhandled Exception in WCF
Exception Handling in WCF - Creating and Throwing Strongly Typed SOAP Fault