Question

I am connecting to a 3rd party API. They have provided me with a WSDL file which i have added by using a web reference. Is it possible to connect via SOAP and send multiple messages across the same connection?

I have created the client from the proxy classes but there doesn’t appear to be a Open() or a Close() method. Does the client connect and disconnect when a method is called?

SampleService client = new SampleService

client.SampleMethod();

Edit:

I have added a “Service Reference” from the WSDL file. The client is constructed from the “PortType” in the WSDL file. There inst a Close() or a Abort() method. The only method on SampleService.client is SampleMethod()

Answer 1

They have provided me with a WSDL file which i have added by using a web reference.

In such case you are not using WCF but ASP.NET WebServices client. In your case it is probably not a big difference but ASP.NET WebServices are mostly for backward compatibility when moving legacy code to new version of .NET framework. Today you should rather use Add Service Reference to use WCF as other also recommended.

SOAP Connection WCF

There is nothing like SOAP connection. SOAP is application protocol tunneled through some transport protocol. In your case the transport protocol is HTTP.

I have created the client from the proxy classes but there doesn’t
appear to be a Open() or a Close() method. Does the client connect and
disconnect when a method is called?

You don’t need to call Open or Close. This is all handled in low level layer of communication stack. By default all HTTP client applications use something called persistent connection. It means that when you access some host for the first time TCP connection is established between your client computer and server hosting target resource. Subsequent calls reuse the same connection. If the connection is not in use for some predefined time (both client and server can have different timeouts) the connection is closed and next time the client wants to call the server it will create a new connection (again you don’t need to bother with this).

So calling the method on SOAP proxy in your application can automatically open connection if no one exists. You don’t need to explicitly close the connection but you should dispose the proxy to release its resources. Connection itself can live after the proxy was disposed and can be reused by another proxy.