xmltypebuilder.cs

一种.net实现ajax方法的类库

/** Copyright (c) 2006, All-In-One Creations, Ltd.
*  All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
* 
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*     * Neither the name of All-In-One Creations, Ltd. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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/**
 * Project: emergetk: stateful web framework for the masses
 * File name: XMLTypeBuilder.cs
 * Description: A type generator to generate simple types from XML record definitions.
 *   
 * Author: Ben Joldersma
 *   
 */

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using System.Reflection.Emit;
using System.Reflection;
using System.Threading;

namespace EmergeTk.Model
{
    class XmlTypeBuilder
    {
        private static AssemblyBuilder asmBuilder = null;
        private static ModuleBuilder modBuilder = null;
        private static Type iRecordListType = null;

        private static void GenerateAssemblyAndModule() 
        {
            if (asmBuilder == null)
            {
                AssemblyName assemblyName = new AssemblyName();
                assemblyName.Name = "XmlTypes";
                AppDomain thisDomain = Thread.GetDomain();
                asmBuilder = thisDomain.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
                modBuilder = asmBuilder.DefineDynamicModule(asmBuilder.GetName().Name, false);
                iRecordListType = TypeLoader.GetType("EmergeTk.Model.IRecordList`1");
            }
        }
        
        public static Type CreateType(string name)
        {
            string basePath = System.Web.HttpContext.Current.Request.MapPath("") + "\\";
            if (!System.IO.File.Exists(basePath + name + ".model"))
            {
                throw new System.IO.FileNotFoundException("Could not load an xml record for model " + name + " at path: " + basePath + name + ".model");
            }
            GenerateAssemblyAndModule();
            TypeBuilder xmlTypeBuilder = modBuilder.DefineType(name, TypeAttributes.Public |
                TypeAttributes.Class, typeof(XmlRecord));
            
            Type xmlType = xmlTypeBuilder.CreateType();
            ColumnInfoManager.RegisterColumns(xmlType, ReadColumnInfos(name));
            return xmlType;
        }

        public static ColumnInfo[] ReadColumnInfos(string name)
        {
            string basePath = System.Web.HttpContext.Current.Request.MapPath("") + "\\";
            XmlDocument doc = new XmlDocument();
            XmlNode node;
            if (System.IO.File.Exists(basePath + name + ".model"))
            {
                doc.Load(basePath + name + ".model");
                node = doc.SelectSingleNode("Model");
            }
            else if (System.IO.File.Exists(basePath + "domain.model"))
            {
                doc.Load(basePath + "domain.model");
                node = doc.SelectSingleNode("//Model[@name,'" + name + "']");
            }
            else
                return null;
            List<ColumnInfo> columns = new List<ColumnInfo>();
            XmlNodeList fields = node.SelectNodes("Column");
            foreach (XmlNode fieldNode in fields)
            {
                string columnName = fieldNode.Attributes["Name"].Value;
                string typeName = fieldNode.Attributes["Type"].Value;
                Type columnType = TypeLoader.GetType(typeName);
                DataType dataType = DataType.None;
                if (columnType != null)
                {
                    if (columnType.IsEnum)
                    {
                        dataType = DataType.None;
                    }
                    else if (fieldNode.Attributes["Relationship"] == null ||
                        fieldNode.Attributes["Relationship"].Value == "One")
                        dataType = DataType.RecordSelect;
                    else
                    {
                        dataType = DataType.RecordList;
                        columnType = iRecordListType.MakeGenericType(columnType);
                    }
                }
                else
                {
                    dataType = (DataType)Enum.Parse(typeof(DataType), typeName);
                    columnType = DataTypeHelper.SystemForDataType(dataType);
                }
                columns.Add(new ColumnInfo(columnName, columnType, dataType));
            }
            return columns.ToArray();
        }
    }
}