据我所知，ADO.Net好像不能实现，用XSD（Schema）判断读取节点的数据类型的功能，而是将所有的数据都作为string。下面这个类用xsd判断元素或属性的数据类型：

using System;
using System.IO;
using System.Xml;
using System.Xml.Schema;

namespace REIT.ALEIS.Xml
{
 /// <summary>
 /// ReitXmlDataValidator 从一个xsd文件中查找
 /// 某个元素或属性的数据类型，并将它转换为.Net的数据类型
 /// </summary>
 public class ReitXmlDataTypeFinder
 {
  private XmlSchema m_Schema;

  public ReitXmlDataTypeFinder(string XSDFilePath)
  {
   FileStream fs;
   try
   {
    fs = new FileStream(XSDFilePath, FileMode.Open);
    m_Schema = XmlSchema.Read(fs,new ValidationEventHandler(ShowCompileError));
    m_Schema.Compile(new ValidationEventHandler(ShowCompileError));//这里一定要编译一次
   }
   catch
   {
    throw;
    }
  }

  public System.Type FindElementType(string ElementName)
  {
   System.Xml.XmlQualifiedName Name = new XmlQualifiedName(ElementName,@"http://www.reitweb.com/fc");
   XmlSchemaObject obj = m_Schema.Elements[Name];
   if(obj==null) return null;

   return FindType(obj);
  }
   
  public System.Type FindAttributeType(string AttributeName)
  {
   System.Xml.XmlQualifiedName AttrName = new XmlQualifiedName(AttributeName,@"http://www.reitweb.com/fc");

   XmlSchemaObject obj = m_Schema.Attributes[AttrName];
   if(obj==null) return null;

   if (obj.GetType() != typeof(XmlSchemaAttribute))
    return null;
   
   XmlSchemaAttribute attr = (XmlSchemaAttribute)obj;
   if(attr.AttributeType!=null)
    return FindType(attr.AttributeType);
   else
    if(attr.SchemaTypeName.Name.CompareTo("anyType")==0) return typeof(object);           
     
   return null;
  }

  private static void ShowCompileError(object sender, ValidationEventArgs e)
  {
   Console.WriteLine("Validation Error: {0}", e.Message);
  }

  private System.Type FindType(object obj)
  {
   if(obj.GetType()==typeof(XmlSchemaSimpleType))
   {
    XmlSchemaSimpleType simpleType = (XmlSchemaSimpleType)obj;
    return simpleType.Datatype.ValueType;
   }
   else if(obj.GetType()==typeof(XmlSchemaComplexType))
   {
    XmlSchemaComplexType complexType = (XmlSchemaComplexType)obj;
    return complexType.Datatype.ValueType;
   }
   else
   {
    XmlSchemaDatatype datatype = (XmlSchemaDatatype)obj;
    return datatype.ValueType;
   }   
  }
 }
}