通过

HttpResponse.Filter 属性

定义

命名空间:
System.Web
程序集:
System.Web.dll

获取或设置一个包装筛选器对象，该对象用于在传输之前修改 HTTP 实体正文。

public:
 property System::IO::Stream ^ Filter { System::IO::Stream ^ get(); void set(System::IO::Stream ^ value); };
public System.IO.Stream Filter { get; set; }
member this.Filter : System.IO.Stream with get, set
Public Property Filter As Stream

属性值

Stream

Stream充当输出筛选器的对象。

例外

HttpException

不允许使用实体进行筛选。

示例

以下示例是一个 ASP.NET 页，该页将 Filter 属性设置为类的新实例 UpperCaseFilter ，该类是一个自定义 Stream 类，该类将传递给大写的所有文本。 有关请求的信息将保存到文本文件中，然后 Filter 设置该属性。 响应筛选器到位后，代码将调用 MapPath 该方法，以获取作为响应内容的源的 TestFile.txt 文本文件的绝对路径。 然后，该代码将创建一个新 StreamReader 对象，以从头到尾读取文本文件，然后调用 Write 该方法在页面上显示文件的内容。

<%@ Page Language="C#" %>
<%@ Import Namespace="System.IO" %>
<%@ import Namespace="Samples.AspNet.CS.Controls"  %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

    private void Page_Load(object sender, EventArgs e)
    {

      // Filter the text to be rendered as all uppercase.
      Response.Filter = new UpperCaseFilterStream(Response.Filter);

      // Convert a virtual path to a fully qualified physical path.
      string fullpath = Request.MapPath("~\\TestFile.txt");

      try
      {
        // Read the contents of the file using a StreamReader.
        using (StreamReader sr = new StreamReader(fullpath))
        while (sr.Peek() >= 0)
        {
          Response.Write((char)sr.Read());
        }
        Message.Text = "Reading the file was successful.";
        
      }
      catch (Exception ex)
      {
        Message.Text = "The process failed.";
      }    
     }

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>HttpResponse.MapPath Example</title>
  </head>
  <body>
    <form id="form1" runat="server">

      <asp:Label id="Message" 
                 runat="server"/>

    </form>
  </body>
</html>

<%@ Page Language="VB" Debug="true"%>
<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="Samples.AspNet.VB.Controls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
     
  Private Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
      
    ' Filter the text to be rendered as all uppercase.
    Response.Filter = New UpperCaseFilterStream(Response.Filter)
    
    ' Convert a virtual path to a fully qualified physical path.
    Dim fullpath As String = Request.MapPath("~\\TestFile.txt")
    
    Try
      
      Dim sr As StreamReader = New StreamReader(fullpath)
      
      Do While sr.Peek() >= 0
        Response.Write(Convert.ToChar(sr.Read()))
      Loop
      sr.Close()
      Message.Text = "Reading the file was successful."
      
    Catch ex As Exception
      
      Message.Text = "The process failed."

    End Try

    
  End Sub

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>HttpResponse.MapPath Example</title>
  </head>
  <body>
    <form id="Form1" runat="server">

      <asp:Label id="Message" 
                 runat="server"/>

    </form>
  </body>
</html>

注解

创建对象Stream并将属性Stream设置为Filter对象时，通过Write传递筛选器发送的所有 HTTP 输出。

适用于