In a scenario, when both client and WCF are being developed simultaneously, how do we provide the datacontracts and operationcontracts to the client?
Apologies for not adding the details earlier. The WCF is created by another team and it is only designed. How do we start client development in this case? Do we need to wait till the WCF is built to have the svc file created?
Add a service reference to your client project to have svcutil create a proxy for you
You can decide to share the data contracts assembly in both projects or to rely on the data contracts dynamically created when adding the service reference
No you don't need to wait for WCF service team. If you have to your project management and WCF service team are pretty bad. The most simple way is to develop your application in iterative way and let your service team to be one iteration ahead. But I don't like this idea because at the end of iteration the service team deliveres "untested" service because you will first use it in the next iteration.
So imho the better way is to implement functionality simultaneously and deliver only working combination of client and service (integration tests during iteration). In this scenario you should first define a contract with WCF service team. Contract is WSDL + XSDs. This technique is sometimes called top down or contract first. The main idea is that you want to integrate together and you want to do simultaneous development. So you need first to design communication interface (service/operation contracts) which will be described by WSDL and transported data (data/message contracts) which will be described in XSDs referenced from WSDL. You can also do this in iterative and incremental way by adding new operations in next iterations. Both teams have to test their code = unit testing and mocking (on client side).
For client development it is enough. You can use created WSDL + XSDs to create service proxy. Service team can use WSCF.blue or another tool to build service skeleton from defined contract.
The biggest drawback of this technique is that you have to be able to write WSDL and XSD or you need to have some good tool (I recommend commercial Altova XMLSpy Enterprise). Alternate way is to define contracts in code on service side and create service without any internal implementation (all methods return null) and lets WCF generate WSDL for you.