HttpUtility Class

Provides methods for encoding and decoding URLs when processing Web requests. This class cannot be inherited.

Namespace: System.Web
Assembly: System.Web (in system.web.dll)

public sealed class HttpUtility
public final class HttpUtility
public final class HttpUtility

The HttpUtility class is used internally by the HttpServerUtility class, whose methods and properties are exposed through the intrinsic ASP.NET Server object. Additionally, the HttpUtility class contains encoding and decoding utility methods that are not accessible from the Server.

The following code example demonstrates the use of the HtmlEncode, HtmlDecode, and ParseQueryString methods of the HttpUtility class.

<%@ Page Language="C#"%>

<script runat="server">

  protected void Page_Load(object sender, EventArgs e)
    String currurl = HttpContext.Current.Request.RawUrl;
    String querystring = null ;

    // Check to make sure some query string variables
    // exist and if not add some and redirect.
    int iqs = currurl.IndexOf('?');
    if (iqs == -1)
      String redirecturl = currurl + "?var1=1&var2=2+2%2f3&var1=3";
      Response.Redirect(redirecturl, true); 
    // If query string variables exist, put them in
    // a string.
    else if (iqs >= 0)
      querystring = (iqs < currurl.Length - 1) ? currurl.Substring(iqs + 1) : String.Empty;
    // Parse the query string variables into a NameValueCollection.
    NameValueCollection qscoll = HttpUtility.ParseQueryString(querystring);
    // Iterate through the collection.
    StringBuilder sb = new StringBuilder();
    foreach (String s in qscoll.AllKeys)
      sb.Append(s + " - " + qscoll[s] + "<br>");
    // Write the results to the appropriate labels.
    ParseOutput.Text = sb.ToString();
    UrlRawOutput.Text = currurl;
    UrlEncodedOutput.Text = HttpUtility.UrlEncode(currurl);
    UrlDecodedOutput.Text = HttpUtility.UrlDecode(currurl);

<head runat="server">
    <title>HttpUtility ParseQueryString Example</title>
    <form runat="server">
      The raw url is: <br />
      <asp:Label  id="UrlRawOutput"
                  runat="server" />
      <br /><br />
      The url encoded is: <br />
      <asp:Label  id="UrlEncodedOutput"
                  runat="server" />
      <br /><br />
      The url decoded is: <br />
      <asp:Label  id="UrlDecodedOutput"
                  runat="server" />
      <br /><br />
      The query string NameValueCollection is: <br />
      <asp:Label  id="ParseOutput"
                  runat="server" />

  • AspNetHostingPermission  for operating in a hosted environment. Demand value: LinkDemand; Permission value: Minimal.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

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