在2.0正式版发布之前，就满天的看到关于DataTable支持序列化的新特性宣传，满以为从此以后使用DataTable就和DataSet一样方便了，结果在应用项目的时候才发现并非那么回事。
DataTable是支持序列化了，但是微软并没有把他做的特别方便，还需要我们自己来做一些工作之后才能够在WebService里面传递DataTable，否则在引用DataTable的时候会发现DataTable变成了一个什么Proxy类型。
首先编写类DataTableSchemaImporterExtension，代码如下：
using System;
using System.Collections.Generic;
using System.Text;
using System.Xml.Serialization.Advanced;
using System.Collections;
using System.Xml.Schema;
using System.Xml.Serialization;
using System.CodeDom;
using System.CodeDom.Compiler;
using System.Xml;
using System.Data;
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namespace Xrinehart.Tools.WebService.SchemaImporter
{
class DataTableSchemaImporterExtension : SchemaImporterExtension
{
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// DataTableSchemaImporterExtension is used for WebServices, it is used to recognize the schema for DataTable within wsdl
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Hashtable importedTypes = new Hashtable();
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public override string ImportSchemaType(string name, string schemaNamespace, XmlSchemaObject context, XmlSchemas schemas, XmlSchemaImporter importer, CodeCompileUnit compileUnit, CodeNamespace mainNamespace, CodeGenerationOptions options, CodeDomProvider codeProvider)
{
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IList values = schemas.GetSchemas(schemaNamespace);
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if (values.Count != 1)
{
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return null;
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}
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XmlSchema schema = values[0] as XmlSchema;
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if (schema == null)
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return null;
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XmlSchemaType type = (XmlSchemaType)schema.SchemaTypes[new XmlQualifiedName(name, schemaNamespace)];
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return ImportSchemaType(type, context, schemas, importer, compileUnit, mainNamespace, options, codeProvider);
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}
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public override string ImportSchemaType(XmlSchemaType type, XmlSchemaObject context, XmlSchemas schemas, XmlSchemaImporter importer, CodeCompileUnit compileUnit, CodeNamespace mainNamespace, CodeGenerationOptions options, CodeDomProvider codeProvider)
{
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if (type == null)
{
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return null;
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}
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if (importedTypes[type] != null)
{
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mainNamespace.Imports.Add(new CodeNamespaceImport(typeof(DataSet).Namespace));
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compileUnit.ReferencedAssemblies.Add(“System.Data.dll”);
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return (string)importedTypes[type];
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}
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if (!(context is XmlSchemaElement))
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return null;
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if (type is XmlSchemaComplexType)
{
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XmlSchemaComplexType ct = (XmlSchemaComplexType)type;
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if (ct.Particle is XmlSchemaSequence)
{
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XmlSchemaObjectCollection items = ((XmlSchemaSequence)ct.Particle).Items;
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if (items.Count == 2 && items[0] is XmlSchemaAny && items[1] is XmlSchemaAny)
{
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XmlSchemaAny any0 = (XmlSchemaAny)items[0];
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XmlSchemaAny any1 = (XmlSchemaAny)items[1];
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if (any0.Namespace == XmlSchema.Namespace && any1.Namespace == “urn:schemas-microsoft-com:xml-diffgram-v1″)
{
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string typeName = typeof(DataTable).FullName;
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importedTypes.Add(type, typeName);
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mainNamespace.Imports.Add(new CodeNamespaceImport(typeof(DataTable).Namespace));
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compileUnit.ReferencedAssemblies.Add(“System.Data.dll”);
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return typeName;
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}
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}
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}
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}
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return null;
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}
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}
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}
为此类添加进一个项目中，并将此项目进行强命名后编译。
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然后，把该Assembly程序集加入到GAC中。
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最后修改本机的machine.config，代码如下：
<sectionGroup name=”system.xml.serialization” type=”System.Xml.Serialization.Configuration.SerializationSectionGroup, System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089″>
<section name=”schemaImporterExtensions” type=”System.Xml.Serialization.Configuration.SchemaImporterExtensionsSection, System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089″ />
<section name=”dateTimeSerialization” type=”System.Xml.Serialization.Configuration.DateTimeSerializationSection, System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089″ />
<section name=”xmlSerializer” type=”System.Xml.Serialization.Configuration.XmlSerializerSection, System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089″ requirePermission=”false” />
</sectionGroup>
<system.xml.serialization>
<schemaImporterExtensions>
<add name=”dataTableSchemaImporterExtension” type=”Xrinehart.Tools.WebService.SchemaImporter.DataTableSchemaImporterExtension, Xrinehart.Tools.WebService.SchemaImporter,Version=1.0.0.0,Culture=neutral,PublicKeyToken=5a627ce15fb94702″ />
</schemaImporterExtensions>
</system.xml.serialization>
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完成以上的步骤后，再编译WebService，重新引用（或者更新Web引用），就可以正确的识别DataTable类型了。
其实DataTable只实现了序列化，但WebService并不能自己反序列化为可识别的格式，所以需要自己手动增加。由此可以衍生为各种业务实体BussinessEntity类对象也可以通过以上方式实现直接传递。
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希望对大家有所帮助。
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来源:网络
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