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See Search Results As You Type - An ASP.NET AJAX Control

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4.21/5 (10 votes)
11 Apr 2008CPOL3 min read 133.8K   8.7K   67   27
A search box that updates the page with search results as you type

DelayedSubmitDemo

Introduction

Highrise and other new AJAX enabled tools have this feature that when you type in a search query, it automatically updates the search results below. It's almost like an auto-complete box, but with the full results on the page instead of a dropdown list below the control. Unfortunately, I didn't find anything like this in the Microsoft ASP.NET AJAX Toolkit. So, I decided that this was a good way to finally dive into the AJAX Control Toolkit.

Here is the result: Live Demo.

It's my first AJAX control, so I'm sure there is room for improvements. I've tested it in Internet Explorer 7, Firefox and Safari. Seems to work fine in all of them.

Background

I used the Membership Editor Example from Peter Keller and TextChangedBehavior.js from Garbin as my inspiration and resource, but started with a VS ASP.NET AJAX Control Project to get the framework up and running.

The Use Case

The user starts typing his search query into the textbox. After he types in the first few characters of the keyword he is looking for, he pauses. Magically, all search results that fit his query so far appear below. If he types in more of the keyword, the results are updated accordingly.

Example: A user is searching for a contact. He types Bl and stops. The names that now show up could include:

  • Blaettler
  • Blatt
  • Blackmore
  • Bloomfield
  • Blodgett
  • Blum

Now, he types another letter, let's say, o, and the list reduces itself to:

  • Bloomfield
  • Blodgett

The Control

There is really only JavaScript code that has functionality. The only thing the code does is start a time on the keyup event, stop the time on keydown, and after the timer fires, it executes the onchange method of the associated TextBox. This way, we get a delayed postback after the user stops typing and not lots of postbacks when he's still writing something.

JavaScript
_onkeyup : function(ev) {
    var k = ev.keyCode ? ev.keyCode :
                ev.rawEvent.keyCode;
    if (k != Sys.UI.Key.Tab) {
        this._timer.set_enabled(true);
    }
},

_onkeydown : function(ev) {
    this._timer.set_enabled(false);
},

_onTimerTick : function(sender, eventArgs) {
    this._timer.set_enabled(false);

    if(this._text != this.get_element().value) {
        this._text = this.get_element().value;

        this.get_element().onchange();
    }
},

Everything else is just setup and teardown code. There is one property in the C# file called Timeout. This determines how long of a pause the user needs to make until the search results get updated.

Using the Code

Just add this control like any other Extender to your ASPX page, set the TargetControlID, and add a TextChanged handler to the search textbox.

XML
<cc1:DelayedSubmitExtender 
    ID="DisableButtonExtender1" 
    runat="server" 
    Timeout="1000" 
    TargetControlID="TextBox1"/>
<asp:TextBox 
    ID="TextBox1" 
    runat="server" 
    AutoPostBack="True" 
    OnTextChanged="TextBox1_TextChanged" 
    Columns="50"></asp:TextBox>        
<br />
List of matching words:<br />

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="TextBox1" />
    </Triggers>
    <ContentTemplate>
        <asp:Repeater ID="Repeater1" runat="server">
            <HeaderTemplate><ul></HeaderTemplate>
            <ItemTemplate>
                <li><%#DataBinder.Eval(Container, "DataItem[0]")%></li>
            </ItemTemplate>
            <FooterTemplate></ul></FooterTemplate>
        </asp:Repeater>
    </ContentTemplate>
</asp:UpdatePanel>

I would then wrap the search results area in an UpdatePanel. If the TextBox is outside, just add an AsyncPostBackTrigger to the UpdatePanel. Inside the UpdatePanel, you can present your search results. For my example, I just have a list of words.

Code-behind

C#
protected void TextBox1_TextChanged(object sender, EventArgs e)
{
    List<string[] /> items = new List<string[] />();

    for (int i = 0; i < wordlist.Length; i++ )
    {
        if (wordlist[i].StartsWith(
                TextBox1.Text, 
                StringComparison.OrdinalIgnoreCase))
        {
            string[] item = new string[1];
            item[0] = wordlist[i];

            items.Add(item);
        }
    }

    Repeater1.DataSource = items;
    Repeater1.DataBind();
}

In the TextChanged handler on the server side, you need to add your specific search code. As mentioned above, I just display a list of words with a Repeater control. The list is contained in a string array called wordlist.

I would recommend to just have a look at the example. It's very simple, and should show you how this works.

Please let me know how it works and if it is of any use. Good luck!

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Web Developer
United States United States
Remy Blaettler (or Rémy Blättler in Swiss German writing) works as the Chief of the System for Supertext AG.

Supertext is the first online copywriting agency and has over 300 professional freelance writers, journalists, proofreaders and translaters in ints network.


Remy started dabbling with Computers when he was 12 on his fathers 286 PC with Basic, he soon moved to Turbo Pascal and then to C++. The last 3 years were dedicated to C# and some ASP.NET.

Comments and Discussions

 
GeneralMy vote of 3 Pin
Member 1039649318-Sep-14 0:12
Member 1039649318-Sep-14 0:12 
GeneralMy vote of 2 Pin
dareen_15-May-14 10:54
dareen_15-May-14 10:54 
QuestionGood Pin
WassimSaasouh10-Oct-13 21:34
WassimSaasouh10-Oct-13 21:34 
QuestionNew Version? Pin
slavisam30-Sep-13 5:42
slavisam30-Sep-13 5:42 
Questionits good Pin
Faiz_Khan17-Aug-12 21:53
Faiz_Khan17-Aug-12 21:53 
AnswerRe: its good Pin
Remy Blaettler19-Aug-12 22:53
Remy Blaettler19-Aug-12 22:53 
QuestionGood article... Pin
Midhunlal G26-Jun-12 23:51
Midhunlal G26-Jun-12 23:51 
First of all thank you for publishing this great article. This is really helpful for me. Actually I am experiencing an issue with the very newest AjaxToolKit ddl. The textbox change event is only getting fired when I am clicking outside the textbox area. The textbox_change event is not getting fired automatically. Do u know any workaround for this issue?

-Mlg
AnswerRe: Good article... Pin
Remy Blaettler27-Jun-12 2:49
Remy Blaettler27-Jun-12 2:49 
GeneralRe: Good article... Pin
Midhunlal G27-Jun-12 4:56
Midhunlal G27-Jun-12 4:56 
GeneralRe: Good article... Pin
Midhunlal G28-Jun-12 2:00
Midhunlal G28-Jun-12 2:00 
GeneralRe: Good article... Pin
Member 958190931-Jan-13 18:14
Member 958190931-Jan-13 18:14 
QuestionGood stuff! :) Pin
palpacino10-Jan-12 15:02
palpacino10-Jan-12 15:02 
AnswerRe: Good stuff! :) Pin
Remy Blaettler10-Jan-12 22:23
Remy Blaettler10-Jan-12 22:23 
GeneralMy vote of 1 Pin
bolikej2-Jan-11 14:36
bolikej2-Jan-11 14:36 
GeneralDoes not work with RequiredFieldValidator Pin
fronjm054-Mar-10 10:02
fronjm054-Mar-10 10:02 
QuestionHow can I achieve this in .net2.0? Pin
Mohammmed Farooq27-Jul-09 1:45
Mohammmed Farooq27-Jul-09 1:45 
QuestionHow can i use your solution with DynamicPopulate Pin
Member 462413621-Jul-09 20:35
Member 462413621-Jul-09 20:35 
AnswerRe: How can i use your solution with DynamicPopulate Pin
Remy Blaettler21-Jul-09 22:27
Remy Blaettler21-Jul-09 22:27 
GeneralGreat job! Pin
xrobx2-Jun-08 23:01
xrobx2-Jun-08 23:01 
GeneralRe: Great job! Pin
Remy Blaettler26-Jul-08 3:53
Remy Blaettler26-Jul-08 3:53 
Answer"DefaultButton" property is not working [modified] Pin
Member 382740230-Apr-08 4:43
Member 382740230-Apr-08 4:43 
QuestionAutocompleteExtender Pin
Andrei Ion Rînea18-Apr-08 23:33
Andrei Ion Rînea18-Apr-08 23:33 
GeneralRe: AutocompleteExtender Pin
Remy Blaettler21-Apr-08 7:37
Remy Blaettler21-Apr-08 7:37 
AnswerRe: AutocompleteExtender Pin
Andrei Ion Rînea21-Apr-08 8:40
Andrei Ion Rînea21-Apr-08 8:40 
GeneralRe: AutocompleteExtender Pin
Remy Blaettler24-Apr-08 16:49
Remy Blaettler24-Apr-08 16:49 

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