XML serialization problem in C# ASP.NET

Answer 1

You can put

[System.Xml.Serialization.XmlElement(Type = typeof(List<HannaPrintsDataAccess.CustomerAddress>) )]

on the property

HannaPrintsDataAccess

Assuming that the member is in fact an instance of List<T>

Basically, this attribute is required to support inheritance with Xml serialization. That is, if a property is of type IList and the instance is of type List<T> (which inherits from IList), you will need to add that attribute to the property specifying List<T>.

Answer 2

The error message seems pretty clear to me:

Exception Details: System.NotSupportedException: Cannot serialize member HannaPrintsDataAccess.Customer.CustomerAddresses of type System.Collections.Generic.IList`1[[HannaPrintsDataAccess.CustomerAddress, HannaPrintsDataAccess, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]] because it is an interface.

Try replacing the type of HannaPrintsDataAccess.Customer.CustomerAddresses, which is currently IList<CustomerAddress>, with the concrete type (e.g. List<CustomerAddress>) instead of the interface.

Answer 3

As the error message explicitly tells you the XmlSerializer cannot serialize interfaces.

You probably had:

public List<CustomerAddress> CustomerAddresses  { get; set; }

which you changed to:

public IList<CustomerAddress> CustomerAddresses  { get; set; }

which no longer works.

Answer 4

The interface property is still public, so the serializer will still attempt to serialize it (and crash).

Put an XmlIgnore attribute on the interface property like this:

[XmlIgnore]
[HasMany(typeof(CustomerAddress), ColumnKey = "CustomerId", Table = "Customer")]
public virtual IList<CustomerAddress> CustomerAddresses
{
    get
    {
        return this._customerAddresses;
    }
    set
    {
        this._customerAddresses = value;
    }
}

You List implementation is screwed up also. Add this declaration right below your IList<CustomerAddress> property declaration:

public List<CustomerAddress> CustomerAddresses
{
    get
    {
        return (List<CustomerAddress>)this._customerAddresses;
    }
    set
    {
        this._customerAddresses = value;
    }
}

HTH...

P.S. For future reference, remember that all public properties are visible to the xml serializer, and it will try to serialize them. Make sure to put XmlIgnore attributes on the properties that should not be serialized.