Wcf Transactions

Wcf provides transaction so operations(wcf methods) those are part of a single work unit can be called in a transaction. Operations could be from same or different wcf services.

If any one method out of all methods called in one transaction fails & thrown exception then all other method's operations also rolled back.
Three options are available of transaction flow:

• Allowed: Marked service method can be called with in transaction or without transaction
• NotAllowed: Marked service method can't be called in transaction
• Mandatory: Marked service method must be called in transaction only

Steps to make Wcf service transaction enabled:

• Create binding tag with attribute transactionFlow is true

    <bindings>

      <wsHttpBinding>

        <binding name ="TransBind" transactionFlow="true"></binding>

      </wsHttpBinding>

    </bindings>

• Assign binding name to bindingConfiguration attribute of endpoint

    <services>

      <service name="WcfTranService1.Service1" behaviorConfiguration="serviceBehavior">

        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"></endpoint>

        <endpoint address="" binding="wsHttpBinding" contract ="WcfTranService1.IService1" bindingConfiguration="TransBind"></endpoint>

      </service>

    </services>

• Mark method in interface with TransactionFlowOption.allowed in TransactionFlow 

        [OperationContract]      

        [TransactionFlow(TransactionFlowOption.Allowed)]

        void SetData(int value);

• Mark method in service concrete class with TransactionScopeRequired=true in operation behavior

        [OperationBehavior(TransactionScopeRequired=true)]

        public void SetData(int value)

        {

            //return string.Format("You entered: {0}", value);           

            try

            {

                SqlConnection con = new SqlConnection("Initial Catalog= testdb; Data Source= GEN-LAP-00011\\SQLEXPRESS; Integrated Security=SSPI;");

                SqlCommand com = new SqlCommand("insert into tb_city (Name, IsActive) Values(Mumbai service" + value + "',1)", con);

                con.Open();

                com.ExecuteNonQuery();

                con.Close();

            }

            catch (Exception ex)

            {

                throw ex;

            }

        }

• Call all methods of a single work unit in one transaction. Methods could be from same or different wcf services
• Call Complete() method of transaction object if no error
• Call Dispose() method of transaction in case of error
  
  TransactionScope - System.Transactions

        protected void Page_Load(object sender, EventArgs e)

        {

            using (TransactionScope tr = new TransactionScope(TransactionScopeOption.RequiresNew))

            {

                try

                {

                    ServiceReference1.Service1Client _client1 = new ServiceReference1.Service1Client();

                    ServiceReference2.Service1Client _client2 = new ServiceReference2.Service1Client();

                    _client1.SetData(1);

                    _client2.SetData(2);

                    tr.Complete();

                }

                catch(Exception ex)

                {

                    tr.Dispose();

                }

            }

        }