Retrieve Metadata

This sample demonstrates how to implement a client that dynamically retrieves metadata from a service to choose an endpoint with which to communicate. This sample is based on the Getting Started Sample. The service has been modified to expose two endpoints—an endpoint at the base address using the basicHttpBinding binding, and a secure endpoint at {baseaddress}/secure using the wsHttpBinding binding. Instead of configuring the client with the endpoint addresses and bindings, the client dynamically retrieves the metadata for the service using the MetadataExchangeClient class and then imports the metadata as a ServiceEndpointCollection using the WsdlImporter class.

The client application uses the imported ServiceEndpointCollection to create clients to communicate with the service. The client application iterates through each retrieved endpoint and communicates with each endpoint that implements the ICalculator contract. The appropriate address and binding are provided with the retrieved endpoint, so that the client is configured to communicate with each endpoint, as shown in the following sample code.

// Create a MetadataExchangeClient for retrieving metadata.
EndpointAddress mexAddress = new EndpointAddress(ConfigurationManager.AppSettings["mexAddress"]);
MetadataExchangeClient mexClient = new MetadataExchangeClient(mexAddress);

// Retrieve the metadata for all endpoints using metadata exchange protocol (mex).
MetadataSet metadataSet = mexClient.GetMetadata();

//Convert the metadata into endpoints.
WsdlImporter importer = new WsdlImporter(metadataSet);
ServiceEndpointCollection endpoints = importer.ImportAllEndpoints();

CalculatorClient client = null;
ContractDescription contract = ContractDescription.GetContract(typeof(ICalculator));
// Communicate with each endpoint that supports the ICalculator contract.
foreach (ServiceEndpoint ep in endpoints)
{
    if (ep.Contract.Namespace.Equals(contract.Namespace) && ep.Contract.Name.Equals(contract.Name))
    {
        // Create a client using the endpoint address and binding.
        client = new CalculatorClient(ep.Binding, new EndpointAddress(ep.Address.Uri));
        Console.WriteLine("Communicate with endpoint: ");
        Console.WriteLine("   AddressPath={0}", ep.Address.Uri.PathAndQuery);
        Console.WriteLine("   Binding={0}", ep.Binding.Name);
        // Call operations.
        DoCalculations(client);

        //Closing the client gracefully closes the connection and cleans up resources.
        client.Close();
    }
}

The client console window displays the operations sent to each of the endpoints, displaying the address path and binding name.

To set up, build, and run the sample

1. Ensure that you have performed the One-Time Setup Procedure for the Windows Communication Foundation Samples.

2. To build the C#, C++, or Visual Basic .NET edition of the solution, follow the instructions in Building the Windows Communication Foundation Samples.

3. To run the sample in a single- or cross-machine configuration, follow the instructions in Running the Windows Communication Foundation Samples.

Note:

The samples may already be installed on your machine. Check for the following (default) directory before continuing. <InstallDrive>:\WF_WCF_Samples If this directory does not exist, go to Windows Communication Foundation (WCF) and Windows Workflow Foundation (WF) Samples for .NET Framework 4 to download all Windows Communication Foundation (WCF) and WF samples. This sample is located in the following directory. <InstallDrive>:\WF_WCF_Samples\WCF\Basic\Client\RetrieveMetadata