Transaction in WCF with self hosting

This article is about how to implement WCF with Transaction at service level and self hosting in Windows application.

Transactions:

A transaction is a unit of work that is performed against a database. Transactions are units or sequences of work accomplished in a logical order, whether in a manual fashion by a user or automatically by some sort of a database program.

Transactions have four standard properties, called ACID properties:

Atomicity: ensures that all operations within the work unit are completed successfully; otherwise, the transaction is aborted at the point of failure, and previous operations are rolled back to their former state.

Consistency: ensures that the database properly changes states upon a successfully committed transaction.

Isolation: enables transactions to operate independently of and transparent to each other.

Durability: ensures that the result or effect of a committed transaction persists in case of a system failure.

Steps:
1.  Add WCF project.
2.  Add System.Transactions DLL to WCF Service project, this DLL contains Transaction related operations
3. Add your method to interface and decorate method with TransactionFlow attribute, 3 options are available in TransactionFlowOption enum

TransactionFlowOption.Allowed – transaction may or may not be followed

TransactionFlowOption.Mandatory – transaction must be followed

TransactionFlowOption.NotAllowed – transaction not allowed

Example:

        [OperationContract]

        [TransactionFlow(TransactionFlowOption.Mandatory)]

        void TransferAmountUsingSql(ulong amount);

4. Implement method with operation behaviour (set TransactionScopeRequire= True and TransactionAutoComplete=true) in interface as follows

By setting TransactionScopeRequire= True, we make the particular function can only be called with TransactionScope from client.

By setting TransactionAutoComplete=true, we make the transaction to commit automatically once its complete its process


Example:
[OperationBehavior(TransactionScopeRequired=true,TransactionAutoComplete=true)]
        public void TransferAmountUsingSql(ulong amount)
        {
            using (SqlConnection conn=new SqlConnection("your Connection string here"))
            {
                using (SqlCommand cmd=new SqlCommand("your Cmd Text here",conn))
                {
                    //your code logic here
                    cmd.ExecuteNonQuery();
                }                
            }
        }


5. Modify configuration file to allow transaction, by setting transactionFlow=”true” 

<bindings>
      <wsHttpBinding>
        <binding name="transactionExample" transactionFlow="true"></binding>
      </wsHttpBinding>
</bindings>


6. Create client application and consume WCF service as follows,

using (TransactionScope transScrope=new TransactionScope(TransactionScopeOption.Required))
            {
                try
                {
                    ulong amount=Convert.ToUInt64(txtAmount.Value);

                    wcfTransaction.TransferAmountSuccess(amount);

                    lblResult.Text = "Succeed";
                }
                catch (Exception ex)
                {   
                    lblResult.Text = ex.Message;
                }
                finally                
                {
                    transScrope.Complete();                    
                }
            }
        }


Project Description:
I enclosed sample project to demonstrate Transaction in WCF with self hosting
Download WCF Sample