title: calling method in helper class exposed by wcf service class
body: <p>In short: Trying to write a wcf service for a winform-app that invokes a stored procedure on a webserver. 
  So far no problem - my service exposes the method "execStp(string nameOfStoredProcedure, stpParamList parameterList)"</p>
  
  <pre><code> [OperationContract]
          int execStp(string stpName, srsWcfLib.Utilities.stpParamList paramList);
  </code></pre>
  
  <p>where stpParamList is another class holding  of a third class stpParams (which basically holds a name/value pair of an SqlParameter</p>
  
  <p>To add parameters to the list, I wrote a method in the second class</p>
  
  <pre><code>public void addParameter(string ParamName, object ParamValue)
          {
              this._Parameters.Add(new stpParam(ParamName, ParamValue));
          } 
  List&lt;stpParam&gt; _Parameters = new List&lt;stpParam&gt;();
  
      [DataMember]
      public List&lt;stpParam&gt; Parameters
      {
          get { return _Parameters; }
          set { _Parameters = value; }
      }
  </code></pre>
  
  <p>When instantiating the List-class in the win-app</p>
  
  <pre><code>stpParamList stpParams = new stpParamList();
  </code></pre>
  
  <p>I can access <code>stpParams.Parameters</code>, but NOT <code>stpParams.addParameter (name, value);</code></p>
  
  <p>What am I missing (obviously)...?</p>
  
  <p>Thank you,
  Reinhard</p>