这是正在开发的XML数据库的一个功能，我需要动态根据一个业务实体类型创建一个XSD架构文件，并使用其对最后的XML数据文件进行约束。

目前该功能仅仅是一个原型，还有待细化改进。例如在实体的成员上用一些特定的Attribute标明该成员要被保存的形态。

第一部分：业务实体类

(作为演示目的，我将所有的类型定义在一个文件里，同时每个类都只有少量简单的属性成员）

此处特别注意的是，Order这个类是很复杂的，它包含了一系列的OrderItem，而OrderItem又包含了Product对象。

using System;
using System.Collections.Generic;
using System.Text; namespace DataEntities
{public class Order{public int OrderID { get; set; }public string CustomerID { get; set; }public int EmployeeID { get; set; }public DateTime OrderDate { get; set; }public List<OrderItem> OrderItems { get; set; } public override string ToString(){StringBuilder sb = new StringBuilder();sb.AppendFormat("\t{0}\t{1}\t{2}\t{3}", OrderID, CustomerID, EmployeeID, OrderDate);sb.AppendLine();foreach (var item in OrderItems){sb.AppendFormat("\t\t{0}\t{1}\t{2}\n", item.Product.ProductName, item.UnitPrice, item.Quantity);}return sb.ToString();} } public class OrderItem {public int OrderId { get; set; }public Product Product { get; set; }public decimal UnitPrice { get; set; }public decimal Quantity { get; set; }}public class Product {public int ProductId { get; set; }public string ProductName { get; set; }}
}

第二部分：生成XSD的工具类(Utility.cs)

using System;
using System.Xml.Linq;
using System.Collections;
using System.Xml;namespace XMLDatabase
{public class Utility{/// <summary>/// 使用指定类型生成一个架构文件/// </summary>/// <typeparam name="T"></typeparam>public static void XsdGenerate<T>(XmlWriter xw) {Type t = typeof(T);XNamespace xn = "http://www.w3.org/2001/XMLSchema";XDocument doc = new XDocument(new XDeclaration("1.0", "utf-8", "yes"),new XElement(xn + "schema",new XAttribute("elementFormDefault", "qualified"),new XAttribute(XNamespace.Xmlns + "xs", "http://www.w3.org/2001/XMLSchema"),new XElement(xn+"element",new XAttribute("name","Table"),new XAttribute("nillable","true"),new XAttribute("type","Table"))));XElement tableElement = new XElement(xn + "complexType",new XAttribute("name", "Table"));tableElement.Add(new XElement(xn + "sequence",new XElement(xn + "element",new XAttribute("minOccurs", "0"),new XAttribute("maxOccurs", "unbounded"),new XAttribute("name","Row"),new XAttribute("type",t.Name))),new XElement(xn + "attribute",new XAttribute("name", "CreateTime"),new XAttribute("type", "xs:string")));doc.Root.Add(tableElement);CreateComplexType(t, doc.Root);doc.Save(xw);}private static void CreateComplexType(Type t,XElement root) {XNamespace xn = root.GetNamespaceOfPrefix("xs");XElement temp = new XElement(xn + "complexType",new XAttribute("name", t.Name));#region 循环所有属性foreach (var p in t.GetProperties())//循环所有属性{Type pType = p.PropertyType;string fullType = pType.FullName;//这里仍然是分几种情况if (!GeneralType.Contains(fullType)){var seqelement = temp.Element(xn + "sequence");if (seqelement == null){seqelement = new XElement(xn + "sequence");temp.AddFirst(seqelement);}if (pType.IsEnum)//如果是枚举{seqelement.Add(new XElement(xn + "element",new XAttribute("minOccurs", "0"),new XAttribute("maxOccurs", "1"),new XAttribute("name", p.Name),new XAttribute("type", pType.Name)));XElement enumElement = new XElement(xn + "complexType",new XAttribute("name", pType.Name),new XElement(xn + "attribute",new XAttribute("name", "Enum"),new XAttribute("type", "xs:string")));root.Add(enumElement);}else if (pType.GetInterface(typeof(IList).FullName) != null && pType.IsGenericType)//如果是集合,并且是泛型集合{Type itemType = pType.GetGenericArguments()[0];seqelement.Add(new XElement(xn + "element",new XAttribute("minOccurs", "0"),new XAttribute("maxOccurs", "1"),new XAttribute("name", p.Name),new XAttribute("type", "ArrayOf"+p.Name)));XElement arrayElement = new XElement(xn + "complexType",new XAttribute("name", "ArrayOf" + p.Name),new XElement(xn + "sequence",new XElement(xn + "element",new XAttribute("minOccurs", "0"),new XAttribute("maxOccurs", "unbounded"),new XAttribute("name", itemType.Name),new XAttribute("type", itemType.Name))));root.Add(arrayElement);CreateComplexType(itemType, root);}else if (pType.IsClass || pType.IsValueType){seqelement.Add(new XElement(xn + "element",new XAttribute("minOccurs", "0"),new XAttribute("maxOccurs", "1"),new XAttribute("name", p.Name),new XAttribute("type", pType.Name)));CreateComplexType(pType, root);}}else{//这种情况最简单，属性为标准内置类型，直接作为元素的Attribute即可temp.Add(new XElement(xn + "attribute",new XAttribute("name", p.Name),new XAttribute("type", GeneralType.ConvertXSDType(pType.FullName))));}}#endregiontemp.Add(new XElement(xn + "attribute",new XAttribute("name", "TypeName"),new XAttribute("type", "xs:string")));root.Add(temp);}}
}

第三部分：辅助类型(GeneralType.cs).

这个类型中有一个方法可以将业务实体类型成员属性的类型转换为XSD中 的类型。

using System;
using System.Collections.Generic;
using System.Text;namespace XMLDatabase
{public class GeneralType{private static readonly List<string> generalTypes = new List<string>(){"System.Byte",//typeof(byte).FullName,"System.SByte",//typeof(sbyte).FullName,"System.Int16",//typeof(short).FullName,"System.UInt16",//typeof(ushort).FullName,"System.Int32",//typeof(int).FullName,"System.UInt32",//typeof(uint).FullName,"System.Int64",//typeof(long).FullName,"System.UInt64",//typeof(ulong).FullName,"System.Double",//typeof(double).FullName,"System.Decimal",//typeof(decimal).FullName,"System.Single",//typeof(float).FullName,"System.Char",//typeof(char).FullName,"System.Boolean",//typeof(bool).FullName,"System.String",//typeof(string).FullName,"System.DateTime"//typeof(DateTime).FullName};/// <summary>/// 判断当前给定类型是否为默认的数据类型/// </summary>/// <param name="fullType"></param>/// <returns></returns>public static bool Contains(string fullType){return generalTypes.Contains(fullType);}public static string ConvertXSDType(string fullType){switch (fullType){case "System.String":return "xs:string";case "System.Int32":return "xs:int";case "System.DateTime":return "xs:dateTime";case "System.Boolean":return "xs:boolean";case "System.Single":return "xs:float";case "System.Byte":return "xs:byte";case "System.SByte":return "xs:unsignedByte";case "System.Int16":return "xs:short";case "System.UInt16":return "xs:unsignedShort";case "System.UInt32":return "xs:unsignedInt";case "System.Int64":return "xs:long";case "System.UInt64":return "xs:unsignedLong";case "System.Double":return "xs:double";case "System.Decimal":return "xs:decimal";default:break;}return string.Empty;}}
}

第四部分：单元测试

        /// <summary>///XsdGenerate 的测试///</summary>public void XsdGenerateTestHelper<T>(){XmlWriter xw = XmlWriter.Create("Order.xsd"); // TODO: 初始化为适当的值Utility.XsdGenerate<Order>(xw);xw.Close();}

第五部分： 生成的结果

<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<xs:schema elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"><xs:element name="Table" nillable="true" type="Table" /><xs:complexType name="Table"><xs:sequence><xs:element minOccurs="0" maxOccurs="unbounded" name="Row" type="Order" /></xs:sequence><xs:attribute name="CreateTime" type="xs:string" /></xs:complexType><xs:complexType name="ArrayOfOrderItems"><xs:sequence><xs:element minOccurs="0" maxOccurs="unbounded" name="OrderItem" type="OrderItem" /></xs:sequence></xs:complexType><xs:complexType name="Product"><xs:attribute name="ProductId" type="xs:int" /><xs:attribute name="ProductName" type="xs:string" /><xs:attribute name="TypeName" type="xs:string" /></xs:complexType><xs:complexType name="OrderItem"><xs:sequence><xs:element minOccurs="0" maxOccurs="1" name="Product" type="Product" /></xs:sequence><xs:attribute name="OrderId" type="xs:int" /><xs:attribute name="UnitPrice" type="xs:decimal" /><xs:attribute name="Quantity" type="xs:decimal" /><xs:attribute name="TypeName" type="xs:string" /></xs:complexType><xs:complexType name="Order"><xs:sequence><xs:element minOccurs="0" maxOccurs="1" name="OrderItems" type="ArrayOfOrderItems" /></xs:sequence><xs:attribute name="OrderID" type="xs:int" /><xs:attribute name="CustomerID" type="xs:string" /><xs:attribute name="EmployeeID" type="xs:int" /><xs:attribute name="OrderDate" type="xs:dateTime" /><xs:attribute name="TypeName" type="xs:string" /></xs:complexType>
</xs:schema>

第六部分：合法的数据文件范例

<?xml version="1.0" encoding="utf-8"?>
<Table Name="Orders" CreateTime="2009/8/9 21:59:04"><Row TypeName="DataEntities.Order" OrderID="10249" CustomerID="ABCDEF" EmployeeID="1" OrderDate="2009-08-09T21:59:04.125+08:00"><OrderItems><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="25" Quantity="4"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Pen" /></OrderItem><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="2" Quantity="2000"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Car" /></OrderItem></OrderItems></Row><Row TypeName="DataEntities.Order" OrderID="10249" CustomerID="ABCDEF" EmployeeID="1" OrderDate="2009-08-10T07:29:51.546875+08:00"><OrderItems><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="25" Quantity="4"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Pen" /></OrderItem><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="2" Quantity="2000"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Car" /></OrderItem></OrderItems></Row><Row TypeName="DataEntities.Order" OrderID="10249" CustomerID="ABCDEF" EmployeeID="1" OrderDate="2009-08-10T07:30:13.375+08:00"><OrderItems><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="25" Quantity="4"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Pen" /></OrderItem><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="2" Quantity="2000"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Car" /></OrderItem></OrderItems></Row><Row TypeName="DataEntities.Order" OrderID="10249" CustomerID="ABCDEF" EmployeeID="1" OrderDate="2009-08-10T07:30:43.875+08:00"><OrderItems><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="25" Quantity="4"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Pen" /></OrderItem><OrderItem TypeName="DataEntities.OrderItem" OrderId="10249" UnitPrice="2" Quantity="2000"><Product TypeName="DataEntities.Product" ProductId="1" ProductName="Car" /></OrderItem></OrderItems></Row>
</Table>