Complexity of web service types

Question

I have developed some basic web services using WCF. So far the return types have been fairly simple. Here are the Operation contracts that are working correctly:

[OperationContract]
string Vessel(int ID);

//lists all vessel
[OperationContract]
List<string> Vessels();

[OperationContract]
List<string> PortsLike(string LikeStr);

[OperationContract]
Port GetPort(string name);

These have worked beautifully. I have now tried to push the envelope a bit and tried the following:

[OperationContract]
List<Pair> Vessels(List<string> fields, List<Criterion> criteria); 

Where Pair and Criterion are pretty basic classes that I defined.

unfortunately this latest Operation does not compile. Is this because I have reached the limits of what can be accommodated by web services or am I doing something obviously wrong?

Here are the definitions for Pair and Criterion:

[DataContract]
public class Criterion
{
    [DataMember]
    public string Key { get; set; }
    [DataMember]
    public string Operator { get; set; }
    [DataMember]
    public string Value { get; set; }
}

[DataContract]
public class Pair
{
    [DataMember]
    public string Key { get; set; }

    [DataMember]
    public string Value { get; set; }

    public Pair(string key, string value)
    {
        this.Key = key;
        this.Value = Value;
    }
}

Here is the error I get from the compiler:

Error 1 'VOps.VOpsService' does not implement interface member 'VOps.IVOpsService.Vessels(System.Collections.Generic.List, System.Collections.Generic.List)'. 'VOps.VOpsService.Vessels(System.Collections.Generic.List, System.Collections.Generic.List)' cannot implement an interface member because it is not public.

Answer 1

Have you decorated Pair and Criterion with DataContract attributes + decorated their properties with DataMember attributes?

Answer 2

You should not have [DataMember] on the Pair constructor

Answer 3

I did not declare the service implementation as public.