Linq To SQL 下实现动态表名的映射(转载)

using System;
using System.Collections.Generic;
using System.Data.Linq;
using System.Data.Linq.Mapping;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Xml.Schema;

namespace ALinq.Mapping
{
    class DynamicMappingSource : MappingSource
    {
        class DynamicAttributedMetaModel : MetaModel
        {
            private MetaModel source;
            private const string TypeName = "System.Data.Linq.Mapping.AttributedMetaModel";

            private DynamicMappingSource mappingSource;

            internal DynamicAttributedMetaModel(MappingSource mappingSource, Type contextType)
            {
                this.mappingSource = (DynamicMappingSource)mappingSource;

                var bf = BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.CreateInstance;
                var args = new object[] { mappingSource, contextType };
                source = typeof(DataContext).Assembly.CreateInstance(TypeName, false, bf, null,
                                                   args, CultureInfo.CurrentCulture, null) as MetaModel;
                Debug.Assert(source != null);
            }

            public override MetaTable GetTable(Type rowType)
            {
                if (mappingSource.GetMetaTableName != null)
                {
                    var typeName = "System.Data.Linq.Mapping.AttributedMetaTable";
                    var bf = BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.CreateInstance;
                    var attribute = new TableAttribute { Name = mappingSource.GetMetaTableName(rowType) };
                    var args = new object[] { source, attribute, rowType };
                    var metaTable = typeof(DataContext).Assembly.CreateInstance(typeName, false, bf, null,
                                                        args, CultureInfo.CurrentCulture, null) as MetaTable;
                    return metaTable;
                }
                return source.GetTable(rowType);
            }

            public override MetaFunction GetFunction(MethodInfo method)
            {
                return source.GetFunction(method);
            }

            public override IEnumerable<MetaTable> GetTables()
            {
                return source.GetTables();
            }

            public override IEnumerable<MetaFunction> GetFunctions()
            {
                return source.GetFunctions();
            }

            public override MetaType GetMetaType(Type type)
            {
                return source.GetMetaType(type);
            }

            public override MappingSource MappingSource
            {
                get { return source.MappingSource; }
            }

            public override Type ContextType
            {
                get { return source.ContextType; }
            }

            public override string DatabaseName
            {
                get { return source.DatabaseName; }
            }

            public override Type ProviderType
            {
                get { return source.ProviderType; }
            }
        }


        public Func<Type, string> GetMetaTableName;

        protected override MetaModel CreateModel(Type dataContextType)
        {
            if (dataContextType == null)
            {
                throw new ArgumentNullException("dataContextType");
            }
            return new DynamicAttributedMetaModel(this, dataContextType);
        }
    }

    [Table(Name = "User")]
    class User
    {
        [Column]
        public int ID;

        [Column]
        public string Name;

    }

    class Program
    {
        static void Main(string[] args)
        {
            var mappingSource = new DynamicMappingSource();
            int i = 0;
            mappingSource.GetMetaTableName = delegate(Type type)
                                                 {
                                                     var att = type.GetCustomAttributes(typeof(TableAttribute), true).Single()
                                                                    as TableAttribute;
                                                     Debug.Assert(att != null);

                                                     return att.Name + i;
                                                 };
            var constr = @"Data Source=NOTEBOOK\SQLEXPRESS;Initial Catalog=DemoDataContext;Integrated Security=True";
            var context = new DataContext(constr, mappingSource) { Log = Console.Out };

            i = 1;
            context.GetTable<User>().Select(o => o).ToList();
            i = 2;
            context.GetTable<User>().Select(o => o).ToList();
        }
    }
}

转自:http://www.cnblogs.com/ansiboy/archive/2009/02/07/1385840.html