我們在開發網頁應用程式,時常需要去解析網址(Request.Url)的每個片段,進行一些判斷。例如說 "http://localhost:1897/News/Press/Content.aspx/123?id=1#toc",我們想要取得網址裡第一層目錄的名字(News)用以判斷不同的頁面標題(Page Title)。
我看很多人都用字串的 IndexOf 方法與 Substring 方法:
[code:c#]
Request.Url.PathAndQuery.Substring(1, Request.Url.PathAndQuery.IndexOf("/", 1)-1)
[/code]
這實在太埋沒 .NET 的強大設計了,事實上在 Request 物件就已經提供很多方便的屬性(Property)可供取得網址的片段。
底下這張表就是各種跟 Browser Request 的網址相關的屬性與用法:
| 網址:http://localhost:1897/News/Press/Content.aspx/123?id=1#toc | 
| 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
 | 
所以當你看了這張表之後,你還會想用 Request.Url.PathAndQuery.Substring(1, Request.Url.PathAndQuery.IndexOf("/", 1)-1) 這種寫法嗎?
用這樣寫 Request.Url.Segments[1].Replace("/", "") 不是又短又直覺嗎? ^_^
以下是產生以上表格的程式碼:
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("網址: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
    // 原則上你應該無法從 Request.Url.Fragment 取得任何資料,因為通常 Browser 不會送出 #toc 這個部分
    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();
}
 
注意事項