Modifier

Partager via

HttpServerUtility.HtmlDecode Method

  • Reference

Definition

Namespace:
System.Web
Assembly:
System.Web.dll

Decodes a string that has been encoded to eliminate invalid HTML characters.

To encode or decode values outside of a web application, use the WebUtility class.

Overloads

HtmlDecode(String)

Decodes an HTML-encoded string and returns the decoded string.
HtmlDecode(String, TextWriter)

Decodes an HTML-encoded string and sends the resulting output to a TextWriter output stream.

HtmlDecode(String)

Decodes an HTML-encoded string and returns the decoded string.

public:
 System::String ^ HtmlDecode(System::String ^ s);
public string HtmlDecode (string s);
member this.HtmlDecode : string -> string
Public Function HtmlDecode (s As String) As String

Parameters

s
String

The HTML string to decode.

Returns

String

The decoded text.

Examples

The following example contains the function LoadDecodedFile, which decodes the data from a file and copies it into one string.

<%@ PAGE LANGUAGE = "C#" %>
 <%@ IMPORT NAMESPACE = "System.IO" %>
 
 <html xmlns="http://www.w3.org/1999/xhtml">
 <script runat ="server">
 
    String LoadDecodedFile(String file)
       {
       String DecodedString = "";
       FileStream fs = new FileStream(file, FileMode.Open);
       StreamReader r = new StreamReader(fs);
 
       // Position the file pointer at the beginning of the file.
       r.BaseStream.Seek(0, SeekOrigin.Begin);
       
       // Read the entire file into a string and decode each chunk.  
       while (r.Peek() > -1)
          DecodedString += Server.HtmlDecode(r.ReadLine());
 
       r.Close();
       return DecodedString; 
       }
 
 </script>
 <head runat="server">
 <title>HttpServerUtility.HtmlDecode Example</title>
 </head>
 <body></body>
 </html>


<%@ PAGE LANGUAGE = "VB" %>
<%@ Import Namespace="System.IO" %>
 
<html xmlns="http://www.w3.org/1999/xhtml">
<script runat = "server">
 
   Function LoadDecodedFile(file As String) As String
      Dim DecodedString As String
      Dim fs As New FileStream(file, FileMode.Open)
      Dim r As New StreamReader(fs)
      ' Position the file pointer at the beginning of the file.
      r.BaseStream.Seek(0, SeekOrigin.Begin)
      ' Read the entire file into a string and decode each chunk.
      Do While r.Peek() > -1
         DecodedString = DecodedString & _
            Server.HtmlDecode(r.ReadLine())
      Loop
      r.Close()
      LoadDecodedFile = DecodedString
   End Function
 
</script>
<head runat="server">
    <title> HttpServerUtility.HtmlDecode Example</title>
</head>
<body></body>
</html>

Remarks

HTML encoding makes sure that text is displayed correctly in the browser and not interpreted by the browser as HTML. For example, if a text string contains a less than sign (<) or greater than sign (>), the browser would interpret these characters as the opening or closing bracket of an HTML tag. When the characters are HTML encoded, they are converted to the strings &lt; and &gt;, which causes the browser to display the less than sign and greater than sign correctly. HtmlDecode decodes text that has been transmitted to the server.

This method is a convenient way to access the HttpUtility.HtmlDecode method at run time from an ASP.NET application. Internally, this method uses HttpUtility.HtmlDecode to decode strings.

In the code-behind file for an ASP.NET web page, access an instance of the HttpServerUtility class through the Server property. In a class that is not in a code-behind file, use HttpContext.Current.Server to access an instance of the HttpServerUtility class.

Outside of a web application, use the WebUtility class to encode or decode values.

Applies to

HtmlDecode(String, TextWriter)

Decodes an HTML-encoded string and sends the resulting output to a TextWriter output stream.

public:
 void HtmlDecode(System::String ^ s, System::IO::TextWriter ^ output);
public void HtmlDecode (string s, System.IO.TextWriter output);
member this.HtmlDecode : string * System.IO.TextWriter -> unit
Public Sub HtmlDecode (s As String, output As TextWriter)

Parameters

s
String

The HTML string to decode.

output
TextWriter

The TextWriter output stream that contains the decoded string.

Examples

The following example decodes a string that has been HTML-encoded for transmission over HTTP. It decodes the supplied string named EncodedString which contains the text "This is a <Test String>.", and copies it into the string named DecodedString as "This is a <Test String>.".

String EncodedString = "This is a &ltTest String&gt.";
StringWriter writer = new StringWriter();
Server.HtmlDecode(EncodedString, writer);
String DecodedString = writer.ToString();


Dim EncodedString As String = "This is a &ltTest String&gt."
Dim writer As New StringWriter
Server.HtmlDecode(EncodedString, writer)
Dim DecodedString As String = writer.ToString()

Remarks

HTML encoding makes sure that text is displayed correctly in the browser and not interpreted by the browser as HTML. For example, if a text string contains a less than sign (<) or greater than sign (>), the browser would interpret these characters as the opening or closing bracket of an HTML tag. When the characters are HTML encoded, they are converted to the strings &lt; and &gt;, which causes the browser to display the less than sign and greater than sign correctly.

HtmlDecode decodes text that has been transmitted to the server.

HtmlDecode is a convenient way to access the HttpUtility.HtmlDecode method at run time from an ASP.NET application. Internally, HtmlDecode uses HttpUtility.HtmlDecode to decode strings.

To encode or decode values outside of a web application, use the WebUtility class.

Applies to