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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

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 UrlEncode, UrlDecode, and ParseQueryString methods of the HttpUtility class.

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">

<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);

<html xmlns="" >
<head runat="server">
    <title>HttpUtility Example</title>
    <form id="form1" 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" />


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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0