我们在开发网页应用程式，时常需要去解析网址(Request.Url)的每个片段，进行一些判断。例如说"http://localhost:1897/News/Press/Content.aspx/123?id=1#toc"，我们想要取得网址里第一层目录的名字(News)用以判断不同的页面标题( Page Title)。
我看很多人都用字串的IndexOf 方法与Substring 方法：
Request.Url.PathAndQuery.Substring(1, Request.Url.PathAndQuery.IndexOf("/", 1)-1)
这实在太埋没.NET 的强大设计了，事实上在Request 物件就已经提供很多方便的属性(Property)可供取得网址的片段。
底下这张表就是各种跟Browser Request 的网址相关的属性与用法：
| 網址：http://localhost:1897/News/Press/Content.aspx/123?id=1 | |
| Request.ApplicationPath | / |
| Request.PhysicalPath | D:\Projects\Solution\web\News\Press\Content.aspx |
| System.IO.Path.GetDirectoryName(Request.PhysicalPath) | D:\Projects\Solution\web\News\Press |
| Request.PhysicalApplicationPath | D:\Projects\Solution\web\ |
| System.IO.Path.GetFileName(Request.PhysicalPath) | Content.aspx |
| Request.CurrentExecutionFilePath | /News/Press/Content.aspx |
| Request.FilePath | /News/Press/Content.aspx |
| Request.Path | /News/Press/Content.aspx/123 |
| Request.RawUrl | /News/Press/Content.aspx/123?id=1 |
| Request.Url.AbsolutePath | /News/Press/Content.aspx/123 |
| Request.Url.AbsoluteUri | http://localhost:1897/News/Press/Content.aspx/123?id=1 |
| Request.Url.Scheme | http |
| Request.Url.Host | localhost |
| Request.Url.Port | 1897 |
| Request.Url.Authority | localhost:1897 |
| Request.Url.LocalPath | /News/Press/Content.aspx/123 |
| Request.PathInfo | /123 |
| Request.Url.PathAndQuery | /News/Press/Content.aspx/123?id=1 |
| Request.Url.Query | ?id=1 |
| Request.Url.Fragment | |
| Request.Url.Segments | /News/Press/Content.aspx/123 |
| Request.QueryString["id"] | 1 |
所以当你看了这张表之后，你还会想用Request.Url.PathAndQuery.Substring(1, Request.Url.PathAndQuery.IndexOf("/", 1)-1) 这种写法吗？
用这样写Request.Url.Segments[1].Replace("/", "") 不是又短又直觉吗？ ^_^
以下是产生以上表格的程式码：
protected void Page_Load(object sender, EventArgs e)
{
StringBuilder sb = new StringBuilder();
sb.Append("<table cellpadding=3 cellspacing=0 border=1>");
sb.Append("<tr><td colspan=2>");
sb.Append("网址："http://localhost:1897/News/Press/Content.aspx/123?id=1#toc">http://localhost:1897/News/Press/Content.aspx/123 ?id=1#toc");
sb.Append("</td></tr>");
// Request.ApplicationPath
sb.Append("<tr><td>");
sb.Append("Request.ApplicationPath");
sb.Append("</td><td>");
sb.Append("<b>" + Request.ApplicationPath + "</b>");
sb.Append("</td></tr>");
// Request.PhysicalPath
sb.Append("<tr><td>");
sb.Append("Request.PhysicalPath");
sb.Append("</td><td>");
sb.Append("<b>" + Request.PhysicalPath + "</b>");
sb.Append("</td></tr>");
// System.IO.Path.GetDirectoryName(Request.PhysicalPath)
sb.Append("<tr><td>");
sb.Append("System.IO.Path.GetDirectoryName(Request.PhysicalPath)");
sb.Append("</td><td>");
sb.Append("<b>" + System.IO.Path.GetDirectoryName(Request.PhysicalPath) + "</b>");
sb.Append("</td></tr>");
// Request.PhysicalApplicationPath
sb.Append("<tr><td>");
sb.Append("Request.PhysicalApplicationPath");
sb.Append("</td><td>");
sb.Append("<b>" + Request.PhysicalApplicationPath + "</b>");
sb.Append("</td></tr>");
// System.IO.Path.GetFileName(Request.PhysicalPath)
sb.Append("<tr><td>");
sb.Append("System.IO.Path.GetFileName(Request.PhysicalPath)");
sb.Append("</td><td>");
sb.Append("<b>" + System.IO.Path.GetFileName(Request.PhysicalPath) + "</b>");
sb.Append("</td></tr>");
// Request.CurrentExecutionFilePath
sb.Append("<tr><td>");
sb.Append("Request.CurrentExecutionFilePath");
sb.Append("</td><td>");
sb.Append("<b>" + Request.CurrentExecutionFilePath + "</b>");
sb.Append("</td></tr>");
// Request.FilePath
sb.Append("<tr><td>");
sb.Append("Request.FilePath");
sb.Append("</td><td>");
sb.Append("<b>" + Request.FilePath + "</b>");
sb.Append("</td></tr>");
// Request.Path
sb.Append("<tr><td>");
sb.Append("Request.Path");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Path + "</b>");
sb.Append("</td></tr>");
// Request.RawUrl
sb.Append("<tr><td>");
sb.Append("Request.RawUrl");
sb.Append("</td><td>");
sb.Append("<b>" + Request.RawUrl + "</b>");
sb.Append("</td></tr>");
// Request.Url.AbsolutePath
sb.Append("<tr><td>");
sb.Append("Request.Url.AbsolutePath");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.AbsolutePath + "</b>");
sb.Append("</td></tr>");
// Request.Url.AbsoluteUri
sb.Append("<tr><td>");
sb.Append("Request.Url.AbsoluteUri");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.AbsoluteUri + "</b>");
sb.Append("</td></tr>");
// Request.Url.Scheme
sb.Append("<tr><td>");
sb.Append("Request.Url.Scheme");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.Scheme + "</b>");
sb.Append("</td></tr>");
// Request.Url.Host
sb.Append("<tr><td>");
sb.Append("Request.Url.Host");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.Host + "</b>");
sb.Append("</td></tr>");
// Request.Url.Port
sb.Append("<tr><td>");
sb.Append("Request.Url.Port");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.Port + "</b>");
sb.Append("</td></tr>");
// Request.Url.Authority
sb.Append("<tr><td>");
sb.Append("Request.Url.Authority");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.Authority + "</b>");
sb.Append("</td></tr>");
// local Request.Url.LocalPath
sb.Append("<tr><td>");
sb.Append("Request.Url.LocalPath");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.LocalPath + "</b>");
sb.Append("</td></tr>");
// Request.PathInfo
sb.Append("<tr><td>");
sb.Append("Request.PathInfo");
sb.Append("</td><td>");
sb.Append("<b>" + Request.PathInfo + "</b>");
sb.Append("</td></tr>");
// Request.Url.PathAndQuery
sb.Append("<tr><td>");
sb.Append("Request.Url.PathAndQuery");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.PathAndQuery + "</b>");
sb.Append("</td></tr>");
// Request.Url.Query
sb.Append("<tr><td>");
sb.Append("Request.Url.Query");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.Query + "</b>");
sb.Append("</td></tr>");
// Request.Url.Fragment
// 原则上你应该无法从Request.Url.Fragment 取得任何资料，因为通常Browser 不会送出#toc 这个部分
sb.Append("<tr><td>");
sb.Append("Request.Url.Fragment");
sb.Append("</td><td>");
sb.Append("<b>" + Request.Url.Fragment + "</b>");
sb.Append("</td></tr>");
// Request.Url.Segments
sb.Append("<tr>");
sb.Append("<td>");
sb.Append("Request.Url.Segments");
sb.Append("</td>");
sb.Append("<td>");
string[] segments = Request.Url.Segments;
foreach (string s in segments)
{
sb.Append("<b>" + s + "</b>");
sb.Append("<br/>");
}
sb.Append("</td>");
sb.Append("</tr>");
sb.Append("</table>");
ltlTable.Text = sb.ToString();
}
注意事项
当程式部署(Deploy)到IIS 6 之后，假设你的网址是http://localhost:1897/News/Press/Content.aspx/123? ，IIS 不知为何会将问号( ? ) 给删除掉，以致于ASP.NET 使用Request.Url.Query 是空字串！如果你的程式有判断到这部分时就要特别注意，因为照理说应该会抓到才对！不知道是不是 IIS 6 的 Bug ？
