HttpResponse.Filter HttpResponse.Filter HttpResponse.Filter HttpResponse.Filter Property

定义

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 实体主体。Gets or sets a wrapping filter object that is used to modify the HTTP entity body before transmission.

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

作为输出筛选器的 Stream 对象。The Stream object that acts as the output filter.

异常

不允许对实体进行筛选。Filtering is not allowed with the entity.

示例

下面的示例是一个 ASP.NET 页,它将Filter属性设置为UpperCaseFilter类的新实例,这是一个Stream自定义类,它将通过其传递的所有文本转换为大写。The following example is an ASP.NET page that sets the Filter property to a new instance of the UpperCaseFilter class, a custom Stream class that converts all text that passes through it to uppercase. 有关请求的信息保存到文本文件中,然后Filter设置属性。The information about the request is saved to a text file, and then the Filter property is set. 响应筛选器就绪后,代码会调用MapPath方法来获取名TestFile.txt为的文本文件的绝对路径,该文本文件用作响应内容的源。After the response filter is in place, the code calls the MapPath method to get the absolute path to a text file named TestFile.txt that serves as the source for the content of the response. 然后,该代码创建一个StreamReader新的对象来读取文本文件,然后Write调用方法以在页面上显示该文件的内容。The code then creates a new StreamReader object to read the text file from beginning to end, and then calls the Write method to display the content of the file on the page.

<%@ 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Stream对象并Filter将属性设置为Stream对象时,通过筛选器发送的Write所有 HTTP 输出都将通过筛选器。When you create a Stream object and set the Filter property to the Stream object, all HTTP output sent by Write passes through the filter.

适用于