ControlFreak

LANGUAGES:VB.NET | C#

ASP.NETVERSIONS: 2.x

Search Box

Master the Art of Search with this Custom Control that Providesthe Ability to Search Your Site, Other Sites, or the Entire Web

By Steve C. Orr

Every respectable Web site of significance needs toprovide search capabilities so users can quickly find the information theyseek. But how does a Web developer provide such functionality? There are myriadways one might go about this. For example, if all the content is stored withinSQL Server, its full text searching capabilities may be of use. But becausethat?s frequently not an option, it?s not too difficult to dream about creatinga custom system that matches keywords to pages. But why reinvent the wheel? Ifyour Web site is publicly available on the Internet, odds are it has alreadybeen thoroughly indexed by Google, MSN Search, and any number of other searchengines.

Leave It to the Professionals

The custom SearchBox control I?ve created harnesses thepower of Google and MSN Search to provide your Web site with all the searchingmuscle it needs. The SearchBox control, shown in Figure 1, is capable of usinga couple different techniques to do the searches, depending on how youconfigure it.

Figure 1: The SearchBox customcontrol can return search results for a specific Web site or the entire Web.

The first and simplest technique builds an appropriate URLstring and redirects the user to it. At this point the search is handed off toGoogle or MSN Search, whichever has been selected in the control?sSearchProvider property. For example, if searching the Web for informationabout towels, the user could be redirected to the following URL:

http://search.msn.com/results.aspx?q=towels

If the user wanted to search only MSDN for informationabout Babel Fish, this URL could be used:

http://www.google.com/search?q=babel+fish+site%3Amsdn.microsoft.com

Luckily, both Google and MSN Search use similar querystrings, so the same code can be used to build the query string no matter whichsearch site is being used.

To use this Firefox-compatible SearchBox control to returnsearch results for a specific site (such as your Web site), set itsSearchSiteOnly property to True and set the SearchSite property to the publicURL of the Web site. If the SearchSiteOnly property is set to False, theSearchSite property will be ignored and the entire Internet will be searchedfor the word(s) in the Text property. To allow the users to choose whether they?dlike to search the entire Web or a specific site, make sure theShowSearchOptions property is set to True. You can also configure the text thatwill be displayed for both of these radio buttons with the SearchTheWebTextproperty and the SearchSiteText property.

The ButtonBelow property specifies whether the Searchbutton should appear beside the search TextBox or below it. The ButtonTextproperty lets you configure the text that appears on the button.

All these options to configure the appearance of thecontrol are nice, but you don?t even have to show the control to use it. Youcould set its visible property to False, configure some of the propertiesdescribed above, and call the SearchBox?s Search method to kick off the search.

When the Search button is clicked (or the control?s Searchmethod is called) the user will be forwarded to the standard Google or MSNSearch Web site with the results immediately displayed, as shown in Figure 2.

Figure 2: One way to use theSearchBox is to have it redirect the user and their search request to Google?sor MSN Search?s standard results page.

This approach works well, and gives the user great resultsin a hurry. The only downside is that it requires the user to leave your siteto get the search results. Web developers that are trying to increase traffictend to cringe at the thought of sending users away, even if it?s just for aquick search that sends them right back into their site. If only there were agood way to get the search results on the server and then output the resultsinto one of your own pages ...

MSN Search Web Services

Luckily, both Microsoft and Google have introduced Webservices that we can call to get search results via code. I?ve chosen to takeadvantage of Microsoft?s Web service for this version of the SearchBox controlbecause it provides more features than Google?s ? and has less restrictiveterms of use. And have you noticed how much MSN Search has improved recently? Itlooks like Google may have some serious competition in the search arena, afterall.

The SearchBox encapsulates the complexities of calling theMSN Search Web Service. If you choose to use this technique, you need to setthe SearchBox?s SearchProvider property to MSNWebService. You also need to setthe MSNApplicationID property to the ID you got free from Microsoft. To get anID, or to learn more about the MSN Search Web Service, visit http://msdn.microsoft.com/msn/gettingstarted/searchstart/.

Now when the user clicks on the Search button, the controlwill call the Web service, retrieve the search results, and raise aSearchResultsReady event to the page. A DataTable will be passed as a parameterto this event, allowing you to do whatever you wish with the results. Figure 3shows a basic page that received search results from a SearchBox control anddisplayed the results in a GridView control using almost no code:

Protected Sub SearchBox1_SearchResultsReady(ByVal _

 SearchResults AsSystem.Data.DataTable) _

 HandlesSearchBox1.SearchResultsReady

   GridView1.DataSource =SearchResults

   GridView1.DataBind()

End Sub

Figure 3: This page only required acouple lines of code to query the MSN Search Web Service and display theresults in a GridView.

Many Web sites prefer to have some kind of search textboxon nearly every page, and then display the results on a specific search page. That?swhere the PostBackURL property comes in. Set this property to the URL of yourspecial search page; then, in the code behind of that search page, use a couplelines of code to receive the posted values and execute the search:

Protected Sub Page_Load(ByVal sender As Object, _

 ByVal e AsSystem.EventArgs) Handles Me.Load

   IfRequest("SearchBox1$text") IsNot Nothing Then

       SearchBox1.Text =Request("SearchBox1$text")

       SearchBox1.Search()

   End If

End Sub

That?s about all you need to know to start using theSearchBox control, which is available for download (see end of article for details).An overview of the unique properties, events, and methods are shown in Figure4. Simply drag the SearchBox.dll into your Visual Studio 2005 toolbox, thendrag it onto any Web form(s) and you should be good to go.

Figure 4: TheSearchBox control provides a dozen members to make searching quick and easy.

So How Does It Work?

The SearchBox is a custom Web server control. The easiestway to create a custom Web server control is to first create a Web ControlLibrary. This may not be as easy as it sounds if you?ve recently upgraded toVisual Studio 2005, because Microsoft moved things around quite a bit. As youcan see in Figure 5, the option for a Web Control Library can be found underthe Windows category beneath your language of choice. Not a very intuitiveplace to put it, in my opinion, but it?s easy enough to find once you knowwhere it is.

Figure 5: The Web Control Libraryproject type is now located under the Windows category in the Visual Studio2005 New Project dialog box.

The SearchBox class inherits from WebControl andimplements INamingContainer. Composition is used for this control (instead ofRendering), meaning essentially that, internally, controls are instantiatedfrom within the CreateChildControls event. The source code for most of theproperties is fairly boilerplate, so I?ve only listed a few of the more interestingones in Figure 6.

<Bindable(True), Category("Appearance"), _

Description("Shows/Hides the search option radiobuttons"), _

DefaultValue(True)> _

Public Property ShowSearchOptions() As Boolean

 Get

   IfViewState("ShowSearchOptions") IsNot Nothing Then

     Return _

       Convert.ToBoolean(ViewState("ShowSearchOptions"))

     Else

       Return True'default

     End If

 End Get

 Set(ByVal value AsBoolean)

   ViewState("ShowSearchOptions") = value

 End Set

End Property

Public Enum SearchProviderEnum

 MSN = 0

 Google = 1

 MSNWebService = 2

End Enum

Dim _spe As SearchProviderEnum

<Bindable(True), Category("Behavior"),DefaultValue(0), _

Description("Which search method to use")> _

Public Property SearchProvider() As SearchProviderEnum

   Get

       Dim s As String =CStr(ViewState("SearchProvider"))

       If s Is NothingThen

         Return _spe

       Else

         Select CaseConvert.ToInt32(s)

             Case 0

                 ReturnSearchProviderEnum.MSN

             Case 1

                 ReturnSearchProviderEnum.Google

             Case 2

                 ReturnSearchProviderEnum.MSNWebService

         End Select

       End If

   End Get

   Set(ByVal value AsSearchProviderEnum)

       _spe = value

       ViewState("SearchProvider") =value

   End Set

End Property

Figure 6: Thesource code for a few of the more interesting SearchBox properties.

The ShowSearchOptions property is fairly standard,including a few attributes to make the design time experience friendlier. ViewStateis used to ensure values are stored between page postbacks. TheSearchProviderEnum enumeration is used by the SearchProvider property to allowthe developer to select Google, MSN, or MSN?s Web service.

The control is essentially rendered as a TextBox, Button,and two RadioButtons. These child controls are created and configured fromwithin the overridden CreateChildControls event, as shown in Figure 7.

Private WithEvents _txt As TextBox

Private WithEvents _radio1 As RadioButton

Private WithEvents _radio2 As RadioButton

Private WithEvents _btn As Button

Protected Overrides Sub CreateChildControls()

   MyBase.CreateChildControls()

   'create a container forall the controls

   Dim pnl As New Panel()

   pnl.ToolTip = Me.ToolTip

   pnl.CssClass =Me.CssClass

   pnl.BackColor =Me.BackColor

   pnl.ForeColor =Me.ForeColor

   pnl.SkinID = Me.SkinID

   'create the textbox& add it to the container

   _txt = New TextBox

   _txt.Text = Me.Text

   _txt.ID ="text"

   pnl.Controls.Add(_txt)

   'create the button

   _btn = New Button

   _btn.Text =Me.ButtonText

   _btn.PostBackUrl =Me.PostBackURL

   _btn.ID ="button"

   pnl.DefaultButton =_btn.ClientID

   If Me.ButtonBelow =False Then pnl.Controls.Add(_btn)

   pnl.Controls.Add(NewLiteralControl("<br/>"))

   'create the searchsite/web radio buttons

   If Me.ShowSearchOptionsThen

       _radio1 = NewRadioButton

       _radio1.Text =Me.SearchSiteText

       _radio1.GroupName ="Search"

       _radio1.Checked =Me.SearchSiteOnly

       _radio1.Style.Add(HtmlTextWriterStyle.FontSize, _

           "x-small")

       _radio1.ID ="SearchSite"

       pnl.Controls.Add(_radio1)

       _radio2 = NewRadioButton

       _radio2.Text =Me.SearchTheWebText

       _radio2.GroupName = "Search"

       _radio2.Checked =Not Me.SearchSiteOnly

       _radio2.Style.Add(HtmlTextWriterStyle.FontSize, _

           "x-small")

       _radio2.ID ="SearchWeb"

       pnl.Controls.Add(_radio2)

       pnl.Controls.Add(NewLiteralControl("<br/>"))

   End If

   If Me.ButtonBelow Thenpnl.Controls.Add(_btn)

   Controls.Add(pnl)

End Sub

Figure 7: TheCreateChildControls method contains the code for instantiating and configuringall the child controls.

A panel control contains all the child controls so they?llstay together in the same area of the Web form, and a few of the base controlproperties are piped through to this panel. Next, the TextBox and Button areinstantiated. The Button is configured to be the panel?s default button, whichis a new feature of ASP.NET 2.0. If the Button is configured to be beside theTextBox, then it is immediately rendered; otherwise, the rendering is delayeduntil the end of this subroutine. The RadioButtons are then instantiated andconfigured if the ShowSearchOptions property is set to True. Finally, all thecontrols are added to the containing panel control.

Figure 8 shows the Search function, which (intuitively)contains the meat of the logic for performing the simple search. It starts byaccepting a search string; otherwise, it uses the search string that waspreviously supplied to the Text property. If the control was configured to usethe MSN Web Search Service, then control is handed off to another function(listed in Figure 9) and an event is raised with the resulting DataTable. Otherwise,the URL and QueryString are concatenated together and the user is redirected tothat address.

Public Sub Search(Optional ByVal SearchText As String ="")

 If SearchText.Trim.Length> 0 Then Me.Text = SearchText

 If Me.Text.Trim.Length >0 Then

   If Me.SearchProvider =_

     SearchProviderEnum.MSNWebService Then

     Dim dt As DataTable

     dt =GetMSNWebSearchWebServiceResults()

     RaiseEventSearchResultsReady(dt)

   Else

     Dim sb As NewStringBuilder()

     If Me.SearchProvider= SearchProviderEnum.MSN Then

       sb.Append("http://search.msn.com/results.aspx?q=")

     Else

       sb.Append("http://www.google.com/search?hl=en&q=")

     End If

     sb.Append(Context.Server.UrlEncode(_txt.Text))

     If Me.SearchSiteOnlyAndAlso _

       Me.SearchSite.Trim.Length > 0 Then

       sb.Append(Context.Server.UrlEncode(" site:"))

       sb.Append(Context.Server.UrlEncode(Me.SearchSite))

     End If

     Context.Response.Redirect(sb.ToString)

   End If

 End If

End Sub

Figure 8: TheSearch method contains most of the logic for performing searches by assemblingthe correct URL and QueryString and redirecting the user to it.

'Queries the MSN search web service and returns a datatable

'containing the results.

'For more info on the MSN search web service, start here:

'http://msdn.microsoft.com/msn/gettingstarted/searchstart/

Protected Function GetMSNWebSearchWebServiceResults() _

      As DataTable

 'initialize variables

   Dim s As New MSNSearchService

 Dim searchRequest As NewSearchRequest

 Dim arraySize As Integer= 1

 Dim sr(arraySize) AsSourceRequest

 sr(0) = New SourceRequest

 sr(0).Source =[SourceType].Web

 sr(0).ResultFields =ResultFieldMask.Title _

        Or ResultFieldMask.Url

 sr(0).Count = 20

 'assemble the searchstring

 Dim SearchText As String= Me.Text & " "

 If Me.SearchSiteOnly _

   AndAlsoMe.SearchSite.Trim.Length > 0 Then

     SearchText += "site:"

     SearchText +=Me.SearchSite

 End If

 'call the msn search webservice

 searchRequest.Query =SearchText

 searchRequest.Requests =sr

 searchRequest.AppID =Me.MSNApplicationID

 searchRequest.CultureInfo= "en-US"

 Dim searchResponse AsSearchResponse

 searchResponse =s.Search(searchRequest)

 'fill a DataTable withthe results

 Dim dt As New DataTable

 Dim dc As NewDataColumn("Title")

 dt.Columns.Add(dc)

 dc = NewDataColumn("Url")

 dt.Columns.Add(dc)

 Dim sourceResponse AsSourceResponse

 For Each sourceResponseIn searchResponse.Responses

   Dim sourceResults AsResult() = sourceResponse.Results

   Dim sourceResult AsResult

   For Each sourceResultIn sourceResults

       Dim dr As DataRow =dt.NewRow

       dr(0) =sourceResult.Title

       dr(1) = sourceResult.Url

       dt.Rows.Add(dr)

   Next

 Next

 Return dt 'return theDataTable

End Function

Figure 9: Thisfunction calls the MSN Search Web Service, transforms the results into aDataTable, and returns the DataTable.

After adding a Web reference to the MSN Search Web Service(located at http://soap.search.msn.com/webservices.asmx?wsdl)the code in Figure 9 should be able to successfully call the MSN Search WebService. The MSN Search Web Service is very rich in functionality, providing awide array of capabilities that are beyond the scope of this article. To learnmore about the MSN Search Web Service, download the MSN Search SDK, whichincludes documentation and several well-commented sample applications.

Search Is King

I think you?ll find the SearchBox to be a valuableaddition to your Visual Studio toolbox. No longer will you need to write customcode to provide basic searching functionality for your Web site. Thisfunctionality should work out of the box for most public Web sites, but I canthink of several nice enhancements for a future version of the control. Forexample, you might add support for other search engines, or you might choose toadd a function to call Google?s search Web service. Another option is to takeadvantage of MSN?s desktop search functionality, which may be useful for Websites that are not publicly available on the Internet (and therefore, areunreachable by standard Web-based search engines). Google has certainly provedthat searching doesn?t have to be boring. The possibilities are endless, so letyour mind wander and see what you come up with.

The full source codefor the SearchBox control is available for download.

Steve C. Orr is anMCSD and a Microsoft MVP in ASP.NET. He?s been developing software solutionsfor leading companies in the Seattlearea for more than a decade. When he?s not busy designing software systems orwriting about them, he can often be found loitering at local user groups andhabitually lurking in the ASP.NET newsgroup. Find out more about him at http://SteveOrr.netor e-mail him at mailto:Steve@Orr.net.