With the help of an http module, a custom config handler and a few lines of code we can add the same ASP.NET 2.0 style URL Mapping to our ASP.NET 1.1 apps.

1) First lets start by creating a new Class Library project named ‘URLMapping_HTTPModule’

2) Then create three files as listed below:

BaseModuleRewriter.vb

Imports System.Web

Public Class BaseModuleRewriter Implements System.Web.IHttpModule

Sub Init(ByVal app As HttpApplication) Implements IHttpModule.Init
     AddHandler app.AuthorizeRequest, AddressOf Me.BaseModuleRewriter_AuthorizeRequest
 End Sub

Sub Dispose() Implements System.Web.IHttpModule.Dispose
 End Sub

Sub BaseModuleRewriter_AuthorizeRequest(ByVal sender As Object, ByVal e As EventArgs)
     Dim app As HttpApplication = CType(sender, HttpApplication)
     Rewrite(app.Request.Path, app)
 End Sub

Overridable Sub Rewrite(ByVal requestedPath As String, ByVal app As HttpApplication)
 End Sub

End Class

URLMappingModule.vb

Imports System.Web Imports System.Configuration

Public Class URLMappingModule Inherits BaseModuleRewriter

Overrides Sub Rewrite(ByVal requestedPath As String, ByVal app As HttpApplication)
     ''Implement functionality here that mimics the 'URL Mapping' features of ASP.NET 2.0
     Dim config As UrlMappingsConfigHandler = CType(ConfigurationSettings.GetConfig("system.web/urlMappings"), UrlMappingsConfigHandler)

    Dim pathOld As String, queryStringArg As String, pathNew As String = ""
     If config.Enabled Then
         pathOld = app.Request.RawUrl

        ''Get the request page without the querystring parameters
         Dim requestedPage As String = app.Request.RawUrl.ToLower
         If requestedPage.IndexOf("?") > -1 Then
             requestedPage = requestedPage.Substring(0, requestedPage.IndexOf("?"))
         End If

        ''Format the requested page (url) to have a ~ instead of the virtual path of the app
         Dim appVirtualPath As String = app.Request.ApplicationPath
         If requestedPage.Length >= appVirtualPath.Length Then
             If requestedPage.Substring(0, appVirtualPath.Length).ToLower = appVirtualPath.ToLower Then
                 requestedPage = requestedPage.Substring(appVirtualPath.Length)
                 If requestedPage.Substring(0, 1) = "/" Then
                     requestedPage = "~" & requestedPage
                 Else
                     requestedPage = "~/" & requestedPage
                 End If
             End If
         End If

        ''Get the new path to rewrite the url to if it meets one
         ''of the defined virtual urls.
         pathNew = config.MappedUrl(requestedPage)

        ''If the requested url matches one of the virtual one
         ''the lets go and rewrite it.
         If pathNew.Length > 0 Then
             If pathNew.IndexOf("?") > -1 Then
                 ''The matched page has a querystring defined
                 If pathOld.IndexOf("?") > -1 Then
                     pathNew += "&" & Right(pathOld, pathOld.Length - pathOld.IndexOf("?") - 1)
                 End If
             Else
                 ''The matched page doesn't have a querystring defined
                 If pathOld.IndexOf("?") > -1 Then
                     pathNew += Right(pathOld, pathOld.Length - pathOld.IndexOf("?"))
                 End If
             End If

            ''Rewrite to the new url
             app.Context.Current.RewritePath(pathNew)
         End If

    End If
 End Sub

End Class

UrlMappingsConfigHandler.vb

Imports System.Configuration Imports System.Xml

Public Class UrlMappingsConfigHandler Implements IConfigurationSectionHandler Dim _Section As XmlNode

Public Function Create(ByVal parent As Object, ByVal configContext As Object, ByVal section As System.Xml.XmlNode) As Object Implements System.Configuration.IConfigurationSectionHandler.Create _Section = section Return Me End Function

Friend Function Enabled() As Boolean ‘’’ Get whether url mapping is enabled in the app.config If _Section.Attributes(“enabled”).Value.ToLower = “true” Then Return True Else Return False End If End Function

Friend Function MappedUrl(ByVal url As String) As String ‘’’ Get the matching “mapped Url” from the web.config file if there is one. Dim x As XmlNode Dim _mappedURL As String = “” For Each x In _Section.ChildNodes If url.ToLower = x.Attributes(“url”).Value.ToLower Then _mappedURL = x.Attributes(“mappedUrl”).Value End If Next Return _mappedURL End Function

3) Now in the ASP.NET 1.1 app that you would like to use this in, just add the following lines to your web.config file:

[code:html]

```