Silverlight实战示例2兼集合属性的妙用--实体的组织(续)

3）数据行DynamicDaTarow.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MEntities
{
    [Serializable]
    public partial class DynamicDaTarow
    {
        public List<Dynamicdatafield> datafields { get; private set; }
        public DynamicDaTarow()
        {
            datafields = new List<Dynamicdatafield>();
        }
    }
   
}

共享代码部分：DynamicDaTarow.Shared.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MEntities
{
    public partial class DynamicDaTarow
    {
        public Dynamicdatafield this[string FieldName]
        {
            get
            {
                Dynamicdatafield theField = null;
                foreach (var fld in datafields)
                {
                    if (fld.FieldName == FieldName)
                    {
                        theField = fld;
                        break;
                    }
                }
                return theField;
            }
        }
        public Dynamicdatafield this[int Index]
        {
            get
            {
                return datafields[Index];
            }
        }
    }
   
}

4）数据表：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MEntities
{
    [Serializable]
    public partial class DynamicDataTable
    {
        public List<DynamicDaTarow> Rows { get; private set; }
        public string TableName { get; set; }
        public List<DynamicDataColumn> Columns { get; private set; }
        public DynamicDataTable()
        {
            Rows = new List<DynamicDaTarow>();
            Columns = new List<DynamicDataColumn>();
        }
    }
}
数据表共享代码部分：DynamicDataTable.Shared.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MEntities
{
    public partial class DynamicDataTable
    {
        public DynamicDataColumn this[string FieldName]
        {
            get
            {
                DynamicDataColumn theCol = null;
                foreach (var col in Columns)
                {
                    if (col.FieldName == FieldName)
                    {
                        theCol = col;
                        break;
                    }
                }
                return theCol;
            }
        }
        public DynamicDataColumn this[int Index]
        {
            get
            {
                return Columns[Index];
            }
        }
    }
}

实体的组织原则：

A）尽可能简单，外部程序集依赖应尽可能少，这样任何其它层都可以引用它，也便于穿越通信层，毕竟实体只是数据的载体； B）索引器无法自动到达客户端，索引器构建主要是为了客户端绑定的时候提供一致的语法和语义； C）如果实体有继承体系，那么索引器可能无法共享到客户端，这个时候可以直接把代码添加到客户端中即可，注意命名空间要保持与服务器一致。