"no parameterless constructor" error in wcf

Question

Hi all:

  When I used wcf ,I wanted that the class which implemented the contract  had a  parameter constructor.But as I did this, I got a error.  

Can anyone tell me how to realize what i want.

 

Answer 1

WCF requires a parameterless constructor to dynamically instantiate a service contract implementation.

However, you do have some options:

1) You can pass in a self instantiated service contract (singleton) instance to the service host.

2) You can add a default constructor to your implementation and call a seperate init method to initialize the instance.

Dave

Answer 2

 

Here is an example for Singleton  with NetMsmqBinding:

Uri queueAddress = new Uri(ImportServiceURL);

NetMsmqBinding msmqbinding = new NetMsmqBinding(NetMsmqSecurityMode.None);

msmqbinding.MaxReceivedMessageSize = 200 * 1024;

msmqbinding.QueueTransferProtocol = QueueTransferProtocol.Srmp;

//Singleton instance with a non-default constructor

DataExchangeService dxs = new DataExchangeService(ConnectionString);

m_hostImport = new ServiceHost(dxs, queueAddress);

ServiceEndpoint sep = m_hostImport.AddServiceEndpoint(typeof(IDataExchange), msmqbinding, queueAddress);

//sep.Behaviors.Add(new TransactedBatchingBehavior(1));

m_hostImport.Open();

Answer 3

Got it .

Thanks , Dave and T.Ramesh