Question

I am trying to pass an object via WCF. I can pass strings, ints etc no problem, but this list of objects will not work.

Here are my 2 specific errors:

Error 1:

The best overloaded method match for
 'test.ServiceReference1.JobsClient.FilesToControl(test.ServiceReference1.Item[])'
 has some invalid arguments

Error 2:

Argument 1: cannot convert from 'System.Collections.Generic.List<test.Site1.Item>'
 to 'test.ServiceReference1.Item[]'

This is the function I am trying to call within asp.net:

// Commit the files
ServiceReference1.JobsClient Client = new ServiceReference1.JobsClient();
Client.Endpoint.Address = new System.ServiceModel.EndpointAddress("http://" +   DropDownListSystems.SelectedValue + ":8732/FactoryAudit/");
test.ServiceReference1.ReturnClass ControlFiles_Result;
ControlFiles_Result = Client.FilesToControl(lstNewItems);

lstNewItems (the object I am trying to pass) is defined as the following code:

List<Item> lstNewItems = new List<Item>(); // Control Items  

Item is defined as:

public class Item
{
    public Item(string Paramater, string Type)
    {
        _Paramater = Paramater;
        _Type = Type;

    }

    private string _Paramater;

    public string Paramater
    {
        get { return _Paramater; }
        set { _Paramater = value; }
    }

    private string _Type;

    public string Type
    {
        get { return _Type; }
        set { _Type = value; }
    }
}

Now in the WCF service I have the following function which accepts a list of items:

//Files Manager
public  ReturnClass FilesToControl(List<Item> ItemsToControl)

{
return new ReturnClass(1, String.Empty, String.Empty, null, null, null);
}

The service contract is defined as:

[ServiceContract]
public interface IJobs
{
     //Files Manager
     [OperationContract]
     ReturnClass FilesToControl(List<Item> ItemsToControl);      
}

The items class is defined in WCF as follows:

[DataContract]
[KnownType(typeof(List<Item>))]
[KnownType(typeof(Item))] 
public class Item
{
   public Item(string Paramater, string Type)
   {
       _Paramater = Paramater;
       _Type = Type;

   }
   [DataMember]
   private string _Paramater;
   [DataMember]
   public string Paramater
   {
       get { return _Paramater; }
       set { _Paramater = value; }
   }
   [DataMember]
   private string _Type;
   [DataMember]
   public string Type
   {
       get { return _Type; }
       set { _Type = value; }
   }
}

Answer 1

What’s lstNewItems in your asp code?

To work it should be an Item[]. Even though you take a List<Item> in the WCF code, the default settings for proxy code generated by WCF is to use arrays for collections.

Edit

With the latest edit in place, the problem is possible to find:

The error message shows that the FilesToControl proxy method accepts an array (Item[])

Error 1 The best overloaded method match for
‘test.ServiceReference1.JobsClient.FilesToControl(test.ServiceReference1.Item[])’
has some invalid arguments

You pass in a List<Item>:

List<Item> lstNewItems = new List<Item>();
//....
ControlFiles_Result = Client.FilesToControl(lstNewItems);

There are three ways to fix this.

• Change lstNewItems to be of type Item[] instead.
• Change the settings of the service reference (which you’ve added to be able to call your WCF) to use List<T> as the default collection type.
• Change the call to convert to an array.

The latter can be done through a call to ToArray:

ControlFiles_Result = Client.FilesToControl(lstNewItems.ToArray());