定义XSD的过程就是类似设计表结构的过程，二者也可以相互转化。
本文讨论了如何定义XSD文件（XML Schema），然后自动生成实体类，最后生成XML的过程，以及如何根据XSD验证XML文件的合法性。以供大家做项目时参考。
1. 首先在VS2005中添加一个XSD文件。例子XSD可以参考：
http://www.15seconds.com/issue/031209.htm
http://www.cduce.org/manual_schema_samples.html
2. 使用VS2005工具XSD.exe(SDK\v2.0\Bin\xsd.exe)自动生成实体类：
xsd /c /namespace:myCompany /language:CS temp1.xsd
也可以生成DataSet类型的类:
xsd /dataset /language:CS temp1.xsd
( 类文件和XSD之间可以相互转换，也就是说，你也可以先生成类，然后自动生成XSD)
自动读取XML数据到实体类：
using (FileStream fs = new FileStream(XmlFilePath, FileMode.Open))
{
return (myClassType)xs.Deserialize(fs);
}
3. 如何由XML生成XSD？
- 可以用工具，如XMLSpy，首先打开XML, 然后DTD/Schema -> Generate DTD/Schema, 选择W3c Sehcma即可。
- 此方法不一定能生成确切满足需求的XSD，另需修改。
4. 如何由XSD生成XML？
- 可以用其他工具，如XMLSpy，DTD/Schema -> Generate sample XML file...
- 可以由XSD生成类，然后写代码实例化这个类，最后序列化为XML
- 如何自动给类每个属性设置一个空值：(用反射的方法)
代码示例：
/// Get all properties and set default value
/// </summary>
/// <typeparam name="T">Type</typeparam>
/// <param name="item">Object</param>
private static void ReflctProperties<T>(T item)
{
PropertyInfo[] pty = typeof(T).GetProperties();
Type t = item.GetType();
if (pty != null)
{
foreach (PropertyInfo info in pty)
{
if (!info.CanWrite) continue;
if (info.PropertyType == typeof(String))
{
t.GetProperty(info.Name).SetValue(item, String.Empty, null);
}
if (info.PropertyType == typeof(Boolean))
{
t.GetProperty(info.Name).SetValue(item, true, null);
}
}
}
}
- 反射读取类的属性:
{
PropertyInfo propertyInfo = item.GetType().GetProperty(PropertyName);
if (propertyInfo != null)
{
return propertyInfo.GetValue(item, null);
}
return null;
}
- 如何序列化为XML？
/// Serialize class instance to XML file
/// </summary>
/// <typeparam name="T">type</typeparam>
/// <param name="XMLFileToCreate">XMLFileToCreate</param>
/// <param name="instance">class instance</param>
public void Serialize<T>(string XMLFileToCreate, T instance)
{
if (instance == null) return;
XmlSerializer xs = new XmlSerializer(typeof(T));
using (StreamWriter sw = new StreamWriter(XMLFileToCreate))
{
xs.Serialize(sw, instance);
}
}
(Link: 使用XMLSerializer类持久化数据 )
5. 如何使用XSD来验证XML文件合法性：
- 使用XMLSpy，首先Assign XSD,然后验证 （其实就是设置XML里面引用的schema，注意schema可能引用其他的schema）
- 代码中验证：
public class Validator
{
private string errMsg;
/// <summary>
/// validation Error Msg
/// </summary>
public string validationErrMsg
{
get { return errMsg; }
set { errMsg = value; }
}
/// <summary>
/// Validate XML against schema
/// </summary>
/// <param name="XSD"></param>
/// <param name="XMLFile"></param>
/// <param name="LocationDefined"></param>
/// <returns></returns>
public bool Validate(string XSD, string XMLFile, bool LocationDefined)
{
bool isValid = true;
try
{
Stream schemaFile = null;
XmlReaderSettings settings = new XmlReaderSettings();
ValidationEventHandler SchemaValidationEventHandler = new ValidationEventHandler(ValidationCallBack);
settings.ValidationType = ValidationType.Schema;
settings.ValidationFlags |= XmlSchemaValidationFlags.AllowXmlAttributes;
settings.ValidationFlags |= XmlSchemaValidationFlags.ReportValidationWarnings;
settings.ValidationEventHandler += SchemaValidationEventHandler;
if (LocationDefined == true)
{
settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessInlineSchema;
settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessSchemaLocation;
}
else
{
schemaFile = new FileStream(XSD, FileMode.Open);
XmlSchema tmsSchema = XmlSchema.Read(schemaFile, SchemaValidationEventHandler);
settings.Schemas.Add(tmsSchema);
}
using (XmlReader reader = XmlReader.Create(XMLFile, settings))
{
string test;
while (reader.Read() && isValid == true)
{
test = reader.Name;
}
};
if (schemaFile != null)
{
schemaFile.Close();
}
}
catch (Exception e)
{
validationErrMsg += "Exception occured when validating. " + e.Message;
isValid = false;
}
return isValid;
}
/// <summary>
/// Display any warnings or errors.
/// </summary>
/// <param name="sender"></param>
/// <param name="args"></param>
public void ValidationCallBack(object sender, ValidationEventArgs args)
{
if (args.Severity == XmlSeverityType.Warning)
{
validationErrMsg += "Matching schema not found. No validation occurred." + args.Message;
validationErrMsg = args.Message;
}
else
{
validationErrMsg += "\nValidation error: " + args.Message;
validationErrMsg = args.Message;
}
}
}
#endregion