开源地址重写

自定义条件可以帮助您扩展UrlRewriter.NET 的功能：

下面是创建自定义条件的步骤和方法：

1. 从IRewriteCondition接口创建一个类，此类将在条件被调用的时候执行：

   /// <summary>
   /// Condition that tests the existence of a file.
   /// </summary>
   internal class ExistsCondition : IRewriteCondition
   {
   	/// <summary>
   	/// Constructor.
   	/// </summary>
   	/// <param name="location"></param>
   	public ExistsCondition(string location)
   	{
   		_location = location;
   	}
   
   	/// <summary>
   	/// Determines if the condition is matched.
   	/// </summary>
   	/// <param name="context">The rewriting 
   context.</param>
   	/// <returns>True if the condition is met.</returns>
   	public bool IsMatch(RewriteContext context)
   	{
   		string filename = HttpContext.Current.Server.
   		MapPath(context.Expand(_location));
   		return File.Exists(filename) ||
   		Directory.Exists(filename);
   	}
   
   	private string _location;
   }

2. 从IRewriteConditionParser接口创建一个类，此类是要创建的条件的解析器：

   /// <summary>
   /// Parser for exists conditions.
   /// </summary>
   internal class ExistsConditionParser : IRewriteConditionParser
   {
   	/// <summary>
   	/// Parses the condition.
   	/// </summary>
   	/// <param name="node">The node to parse.</param>
   	/// <returns>The condition parsed, or null 
   if nothing parsed.</returns>
   	public IRewriteCondition Parse(XmlNode node)
   	{
   		XmlNode existsAttr = node.Attributes.
   GetNamedItem("mycondition");
   		if (existsAttr != null)
   		{
   			return new 
   ExistsCondition(existsAttr.Value);
   		}
   		return null;
   	}
   }

3. 注册自定义条件：

   <register parser="MyNamespace.Parsers.ExistsConditionParser,
   MyAssembly" />

4. 使用自定义条件：

   <if mycondition="something">
   	....
   </if>

参考

• 动作
• 条件
• 解析器
• 开源地址重写