c# - Windows Communication Foundation Null Reference Error -

i trying use windows communication foundation(wcf) testing purposes in application , getting null object. new using wcf, appreciated.

from understand, each host has 1 service type(class). have several interfaces , classes want test. goal make 1 master class has instances of others, don't have have several hosts running. below of code.

host-

public class automationwcfhost {     public servicehost host;      public automationwcfhost() {         uri httpurl = new uri("http://localhost:8090/myfun");         host = new servicehost(typeof(myfun), httpurl);         servicemetadatabehavior smb = new servicemetadatabehavior();         smb.httpgetenabled = true;         smb.metadataexporter.policyversion = policyversion.policy15;         host.description.behaviors.add(smb);     }      public void startwcf() {         this.host.open();     }      public void stopwcf(){         this.host.close(); 

interfaces -

[servicecontract] public interface imyfun {     [operationcontract]     string echo(string msg);      idatasources datasources { [operationcontract]get; [operationcontract]set; } }   [servicecontract] public interface idatasources {     [operationcontract]     void add(datasource datasource);     [operationcontract]     void remove(datasource datasource); } 

class - trying make 1 base class don't have have multiple hosts running.

public class myfun : imyfun {      public datasources _datasources;      public myfun () {         _datasources = new datasources();     }      public string echo(string msg) {         return msg;     }      public idatasources datasources { { return _datasources; } set {_datasources = (datasources)value;} } }  public class datasources : idatasources{ ....//several methods , properties } 

test -

public void mytest() {          endpointaddress address = new endpointaddress("http://localhost:8090/myfun");         basichttpbinding binding = new basichttpbinding();         channelfactory<imyfun> factory = new channelfactory<imyfun>(binding, address);         imyfun channel = factory.createchannel();         assert.areequal("test", channel.echo("test"));         idatasources datasources = channel.datasources;         datasources.add(newdatasource);              } 

as step through, runs echo method fine, when does

idatasources datasources = channel.datasources; 

datasources null. makes

datasources.add(newdatasource); 

fails due null exception error.