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 NotInheritable Class HttpUtility
Dim instance As HttpUtility

public final class HttpUtility
public final class HttpUtility
Not applicable.

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="VB" %>

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

<script runat="server">
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)

        Dim currurl As String = HttpContext.Current.Request.RawUrl
        Dim querystring As String = Nothing
        ' Check to make sure some query string variables
        ' exist and if not add some and redirect.
        Dim iqs As Int32 = currurl.IndexOf("?".ToCharArray())
        If (iqs = -1) Then
            Dim redirecturl As String = currurl & "?var1=1&var2=2+2%2f3&var1=3"
            Response.Redirect(redirecturl, True)
            ' If query string variables exist, put them in
            ' a string.
        ElseIf (iqs >= 0) Then
            If (iqs < currurl.Length - 1) Then
                querystring = currurl.Substring(iqs + 1)
            End If
        End If

        ' Parse the query string variables into a NameValueCollection.
        Dim qscoll As NameValueCollection = HttpUtility.ParseQueryString(querystring)
        ' Iterate through the collection.
        Dim sb As New StringBuilder()
        For Each s As String In qscoll.AllKeys
            sb.Append(s & " - " & qscoll(s) & "<br />")
        Next s
        ' Write the results to the appropriate labels.
        ParseOutput.Text = sb.ToString()
        UrlRawOutput.Text = currurl
        UrlEncodedOutput.Text = HttpUtility.UrlEncode(currurl)
        UrlDecodedOutput.Text = HttpUtility.UrlDecode(currurl)
    End Sub

<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" />    

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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0