Silverlight3+WCF遇到的问题（二）：wcf system.servicemodel.communicationexception Virus

　　以前我访问的数据库都是一张表，没有关联，昨天添加了两张表，一共两张表，用户表和用户类型表，然后修改了原来的两个实体类

　　用户信息实体类

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.Serialization;

namespace Domain.Entity
{
    [DataContract]
    public class Customer : INotifyPropertyChanged
    {
        private int _intCustomerId;
        private string _strCustomerName;
        private string _strCustomerCode;
        private CustomerType  _CustomerType;
        private int _intCustomerTypeId;

        [DataMember ]
        public virtual  int CustomerTypeId
        {
            get { return _intCustomerTypeId; }
            set
            {
                _intCustomerTypeId = value;
                OnPropertyChanged("CustomerTypeId");
            }
        }

        [DataMember ]
        public virtual  CustomerType  CustomerType
        {
            get { return this._CustomerType; }
            set
            {

                this._CustomerType = value;
                OnPropertyChanged("CustomerType");
            }
        }

        [DataMember]
        public virtual int CustomerId
        {
            get { return this._intCustomerId; }
            set
            {
                this._intCustomerId = value;
               OnPropertyChanged("CustomerId");
            }
        }
        [DataMember]
        public virtual string CustomerName
        {
            get { return this._strCustomerName; }
            set
            {
                this._strCustomerName = value;
               OnPropertyChanged("CustomerName");
            }
        }
        [DataMember]
        public virtual string CustomerCode
        {
            get { return _strCustomerCode; }
            set
            {
                this._strCustomerCode = value;
                OnPropertyChanged("CustomerCode");
            }
        }

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        #endregion
        private void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

　　用户类型实体类

　　

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.Serialization;

namespace Domain.Entity
{
    [DataContract]
    public class CustomerType : INotifyPropertyChanged
    {
        private string _strCustomerTypeName;
        private int _intCustomerTypeId;
        private IList  <Customer> _customers;
        [DataMember ]
        public virtual  int CustomerTypeId
        {
            get { return this._intCustomerTypeId; }
            set
            {

                this._intCustomerTypeId = value;
                OnPropertyChanged("CustomerTypeId");
            }
        }

        [DataMember]
        public virtual string CustomerTypeName
        {
            get { return this._strCustomerTypeName; }
            set
            {
                this._strCustomerTypeName = value; OnPropertyChanged("CustomerTypeName");
            }
        }
        [DataMember]
        public virtual IList<Customer> Customers
        {
            get { return this._customers; }
            set
            {
                this._customers = value;
                OnPropertyChanged("Customers");
            }
        }
        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        #endregion
        private void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
        public override string ToString()
        {
            return CustomerTypeName;
        }
    }
}

　　

　　请注意上面的这个红色部分IList，本来我是想返回集合的，一想针对接口编程，然后就写了一个IList，可是问题就出来了，原来好好的东西，就跑不了了，一个劲的报错。

　　在SL3客户端的代码

　　

void client_GetCustomerCompleted(object sender, GetCustomerCompletedEventArgs e)
        {
            LayoutRoot.DataContext = e.Result;
        }

　　报错，就在e.Result，报错wcf system.servicemodel.communicationexception  我就开始找啊找，google啊google，很多人提出这个错误，就是没有回答。后来我在这篇请教当返回自定义类型时如何通过<declaredTypes>实现序列化帖子中找到了一些提示信息，他说“查了一些帮助，发现是由于返回类型中有个IList，所以无法序列化”，恍然大悟，还是WCF版的版主Frank Xu Lei厉害啊，哈哈。

　　修改成List就可以了，问题解决。