Well some time ago I posted the code for a jquery plugin to Radiobutton-Groups  ( a jQuery Room for Radiogroups) . As usual, soon after I had finished my code I came across a problem where I had to manage a large group of check buttons. Not a big deal though, after all check buttons are much like radio buttons, except that the later normally should return a value indicating which of the buttons in the group has been selected ( and while there is only one radio button possibly selected at a time, this makes perfect sense ). 

Check buttons in comparison are mostly used to return a bit value – checked or not checked. Before Ajax a check button value was necessary because the only way a checkbox could tell the Server whether it was checked or not was to set its value into the Request.Form collection, but fortunately times are a-changing: Now all we need to know is it’s checked state. Also, check buttons can be grouped together to a logical unit, but it doesn’t make sense for such a group to return a single value as with radio groups - this differences had to be handled in order to create a plug in that would manage both radio- and check button groups.

The outcome was a JQuery plugin, or better two plug ins:

$.fn.Checkbox wraps a check- or radio button Input and its associated text label. The jQuery wrapper is extended with a disable- and enable method that will not only enable/disable the button but also the label – as you can see in the screenshot from one of my apps. 
If the wrapped control is a check button then the native jQuery val()  method is overwritten to set/get true/false values both reflecting and setting the checked state.

Let’s play a typical scenario for a checkbox like this:

<label for="chk">Thirsty ?</label><input type="checkbox" id="chk" />

Assume that you want to uncheck the button, disable it, and change the text of the Label:

with the Checkbox plugin this is a one-liner:

// Create a Checkbox object
var jCheck= $("#chk").Checkbox();
jCheck.uncheck().disable().label.text("Drunk!");
 
// Read the state of our Checkbox
var IsFilled = jCheck.checked();
 
// You can also use the val() method to set/get the checked state
var IsFilled = jCheck.val();
 
// Set the checked state of our Checkbox
jCheck.checked( bIsSober );

Same applies to a Radio Button,  although a single Radio Buttons doesn’t make a lot of sense.
If you want to work with Grouped check- or radio buttons then we use the second plugin:

$.fn.ButtonGroup extends a jQuery container object ( usually a table or fieldset ) that wraps a couple of radio- or checkbox buttons together with their associated labels.  The ButtonGroup then allows you to easily set/get a Radio group's value,  disable- or enable the complete Group (including labels) or only selected buttons. Internally the ButtonGroup is no more than a list of $.fn.Checkbox objects that wrap the check or radio buttons and some code to bring it all together. The modified get() method returns such an extended button object that also  'understands' checked/enable/disable messages.

By default the control expects and returns integer values. If no button is selected at all then

ButtonGroup.val() will return a Zero ( or –1, if Zero is a valid value for one of the Buttons) . These values can be overwritten by an options object passed as a constructor parameter as usual for many jQuery plugins.

Lets create a little button group:

<table id="tbGroup">
    <tr>
        <td><input type="radio" id="rad0" name="radCity" value="1" /></td>
        <td><label for="rad0">German citizen by birth</label></td>
    </tr>                
    <tr>
        <td><input type="radio" id="rad1" name="radCity" value="2" /></td>
        <td><label for="rad1">Acquired German citizenship:</label></td>
    </tr>                
    <tr>
        <td><input type="radio" id="rad2" name="radCity" value="3" /></td>
        <td><label for="rad2">Not a German citizen</label></td>
    </tr>                
</table>

Nothing unusual so far, three Radio buttons ( could be Check buttons as well ) grouped together with a common name property “radCity”.  In this case we use a Table to give our buttons a container ( and proper layout ), but you can also use a div-tag or whatever tags you prefer – this container will  the prime candidate for our ButtonGroup:

Using the ButtonGroup Control:

// Create the Radio ButtonGroup 
var jGroup = $("#tbGroup").ButtonGroup();
 
jGroup.disable(0);                  // Disable the first Button 
jGroup.disable(0,2);                // Disable Buttons 0 and 2
jGroup.val("1");                    // Set a value and so select button 0 
 
var IDRadio = jGroup.val().toInt(); // read the radio group value .
 
jGroup.get(0);                      // returns first button object
jGroup.get(1,2);                    // returns Array with button 1 and 2
jGroup.get("checked");              // returns selected Radio Button
 
 
// Disable all buttons, remove selection, enable one button and select it
if ($Controls.chkNoRelatives.checked()) {
    $Controls.tbGroup.disable().uncheck().get("rad1").enable().checked(true);
}; 
 

This short example might give you an impression about the power and simplicity of this plugin, imagine you’d have to code the last example by hand ! Please visit the ButtonGroup Live Demo Page  for a short demonstration of Radio- and Checkbox Groups.  Comments and Improvements appreciated !

Resources:

• The Source Code ( tomsoft.buttongroup.js )
• ButtonGroup Live Demo Page

Keywords:		jquery, plugins, javascript, checkbutton, radiobutton
Categories:		Framework | JavaScript | jQuery
Advanced:		E-mail | del.icio.us | Permalink | Comments (0) | Comment RSS

User controls are among the better features that ASP.NET has to offer. I use them either whenever I realize that I can use a piece of code and markup somewhere else, but more frequently I write a User Control when things on a webpage are getting crowded and complicated and I want to split my code into smaller pieces.

Very often these "black box" User controls not only contain Html markup and Server code, but also JavaScript and CSS blocks. It is there when a seemingly simple task can get awfully complex - do you want your JavaScript in the Header or (better) in the bottom of the Page ? do you need <%= %> expressions to embed values like ClientID's into the script ? The same applies to CSS Style blocks, they should be placed in the Html Header in order to accelerate Page rendering. And sometimes you may also need expressions to embed WebResource-Urls or other values into the Styles Sheet.

Well, lots of articles have already been written to address this problems, none of them could truly convince me, until I came up with my own simple solution. Here is a short example:

<asp:Literal ID="DebugInfo" runat="server" Visible="false">
  <link href="~/default.css" rel="stylesheet" type="text/css" />
  <script src="C:\Eigene Dateien\Visual Studio 2008\scripts\jquery-debug.js"
              type="text/javascript"></script>     
</asp:Literal>

<script runat="server">

   protected override void OnPreRender(EventArgs e)
   {
       base.OnPreRender(e);

       // load ScriptBlock and replace ClientID's 
       string src = ScriptBlock.Text.Replace( "LABEL_CLIENTID", 
                  this.myLabel.ClientID);
       
       // move it to the bottom of our page
       this.Page.ClientScript.RegisterStartupScript( this.GetType(), 
                  "MyScript", src );

       // load CSS and move it into the Header
       src = Environment.NewLine + CSSBlock.Text;
       this.Page.Header.Controls.Add( new LiteralControl(src));
       
   }
</script>

<!-- Html Markup    -->      
<div id="MyDialog" style="display:none">
   
   <asp:Label ID="myLabel" runat="server"></asp:Label>

</div>


<!-- CSS Block    -->      
<asp:Literal id="CSSBlock" visible="false" runat="server">
    
   <style type="text/css">
      #MyDialog {width:750px; height:365px; }
   </style>
   
</asp:Literal>


<!-- Script Block    -->      
<asp:Literal id="ScriptBlock" visible="false" runat="server">

    <script type="text/javascript">
    
       $(document).ready(function() {
           var objLabel = $("#LABEL_CLIENTID");
           objLabel.html( "My User Control");
       });
    
    </script>
            
</asp:Literal>

The first thing that you have to do is to hide the CSS and Script Blocks in Server-Side Literal-Controls with a Visible=False attribute. This way our code is visible to ASP, but is not rendered into the Page:

<asp:Literal ID="DebugInfo" runat="server" Visible="false">
  <link href="~/default.css" rel="stylesheet" type="text/css" />
  <script src="C:\Eigene Dateien\Visual Studio 2008\scripts\jquery-debug.js"
              type="text/javascript"></script>     
</asp:Literal>

<link href="~/default.css" rel="stylesheet" type="text/css" 
                                   runat="server" visible="false" />

<asp:Literal id="ScriptBlock" visible="false" runat="server">

   <script type="text/javascript">

     $(document).ready(function() {
     var objLabel = $("#LABEL_CLIENTID");
     objLabel.html( "My User Control");
     });
   </script>

</asp:Literal>

The Javascript code is completely embedded into our ASP Server-Side LiteralControl. No need to mess around with encoding the </script> tag, just write and format your JavaScript Code as if you would do in a static html file. Note the LABEL_CLIENTID token, we will use that later to replace the token with a valid ClientID. Usually this kind of solution to overcome ASP.NET containership naming scheme issues uses code blocks like this :

var ctrl = document.getElementById("<%= myLabel.ClientID %>");

Fortunately we can’t use code blocks inside a Literal Control, so we are forced to use something more elegant than this ugly hack. So how do we get the Code into the Page ? This is preferably done in the Pages OnPreRender Event, which is launched as one of the last events during the creation of a page:

// load ScriptBlock and replace ClientID's 
string src = ScriptBlock.Text.Replace( "LABEL_CLIENTID", this.myLabel.ClientID);



// move it to the bottom of our page
this.Page.ClientScript.RegisterStartupScript( this.GetType(), "MyScript", src );

First we load the Content (= our Script ) of the Literal Control and replace the Token with the targeted Controls ClientID.  If you are using some kind of Script Compressor then this would be the right place to strip comments and white spaces etc. 
Next we use the pages ClientScriptManager to  insert our Script into the bottom of our page. If you prefer to insert it into the Header of your page, you can use the approach that we use to insert the CSS Block
:

// load CSS and move it into the Header
src = Environment.NewLine + CSSBlock.Text;
this.Page.Header.Controls.Add( new LiteralControl(src));

Same procedure here: Load the Css Code from the Literal Control, edit it to your heart’s content and then wrap it into a new LiteralControl to add it to the Page.Header Controls collection.

Using this technique you can easily write self contained User Controls with enclosed Scripts and Styles that embed themselves perfectly into the parent page, and as a bonus your get both CSS and JavaScript Intellisense for external files in your User Control …

Keywords:		asp.net user controls, javascript, css, intellisense
Categories:		ASP.NET | CSS | JavaScript | Visual studio
Advanced:		E-mail | del.icio.us | Permalink | Comments (0) | Comment RSS

<div id="container">
    <input type="radio" id="rad1" name="radKult" value="1" />
        <label for="rad1">free drinks</label> 
    <input type="radio" id="rad2" name="radKult" value="2" />
        <label for="rad1">paid drinks</label>
  </div>


// Create RadioGroup wrapper and set/get value
jGroup = $("#container input:radio");    
var sel = jGroup.filter(':checked').val()
jGroup.attr("checked", "checked");

The RadioGroup Control:

• The val() method is overwritten to easily return and set the Radio group's value
• The enable() and disable() methods should enable and disable either the complete group (including labels) or only selected buttons
• The modified get() method will return an extended Radio button object that also understands checked/enable/disable messages

   ////////////////////// RadioGroup //////////////////////////
    

  $.fn.RadioGroup = function() {
      /// <summary>
      /// JQuery plugin that creates a TomSoft.Form.RadioGroup object and 
      /// attaches this to the Wrapper of the RadioGroup-Container.
      /// <returns type="jQuery" />

      if (this.length != 1) {
          throw new Error("bad selector for RadioGroup " + this.selector,
                                           "window.document");
          return this;
      }

      var items = [];
      _init(this);

      // 
      // JQuery object extensions
      //
      this.val = function(value) {
          /// <summary>
          /// Returns the value of the checked radio button within the Group 
          /// or checks the radiobutton with the given value. if the value 
          /// does not exist then the radiogroup remains unchecked
          /// </summary>

          if (arguments.length) {
              value = value.toString();   // setter
              for (var i = 0; i < items.length; ++i) {
                  var j = items[i];
                  j.checked(false);
                  if (value == j.val()) {
                      j.checked(true);
                      break;
                  };
              };
              return this;
          }
          // getter
          var j = this.selected();
          return ((j) ? j.val() : -1);
      };

      this.enable = function(bEnable) {
          /// <summary>
          /// enable/disable RadioGroup and associated Labels
          /// </summary>    
          bEnable = (typeof (bEnable) == 'boolean') ? bEnable : true;
          for (var i = 0; i < items.length; ++i) {
              items[i].enable(bEnable);
          }
          return this;
      };

      this.disable = function() {
          /// <summary>
          /// if called without arguments the method disables all RadioButton
          /// and associated Labels. If numeric arguments are passed then 
          /// all RadioButtons of the group are enabled except those with 
          /// matching the index position.
          /// </summary>
          /// <example>
          ///     $Controls.radioGroupHerkunft.disable(1,4,5); 
          /// </example>    
          if (arguments.length) {
              for (var i = 0; i < items.length; ++i) {
                  // check if pos i is in the argument list to be disabled
                  var bEnable = ($.inArray(i, arguments) == -1);
                  items[i].enable(bEnable);
              };
              return this;
          };
          return this.enable(false);
      };

      this.selected = function() {
          /// <summary>
          /// Returns the checked radiobutton within the Group 
          /// </summary>
          for (var i = 0; i < items.length; ++i) {
              if (items[i].checked()) {
                  return items[i];
              };
          };
          return null;
      };

      this.get = function(index) {
          /// <summary>
          /// Returns modified RadioButton Object by position or ID(s):
          ///
          /// radio.get( 0 )       returns first jRadioLabel
          /// radio.get( 0,2,3 )   returns Array of buttons in Pos 0,2 and 3
          ///                      usage: $.each( radio.get(0,..), 
          ///                             function(){this.disable()})
          /// radio.get("checked") return selected jRadioLabel
          /// radio.get("all")     return list array of all Radio Buttons
          /// </summary>

          var list = [];

          for (var cx = 0; cx < arguments.length; ++cx) {
              var arg = arguments[cx];
              if (typeof (arg) == 'string') {
                  if (arg == "checked")   return this.selected();
                  if (arg == "all")       return items;

                  for (var i = 0; i < items.length; ++i) {
                      if (items[i].radio.id == arg)
                          list.push(items[i]);
                  };
              }
              else if (arg >= 0 && arg < items.length) {
                  list.push(items[arg]);
              };
          };
          if (list.length)
              return (list.length == 1) ? list[0] : list;

          return;
      };

      return this;




      //
      // Initialize the object
      //
      function _init(jObj) {

          var jLabel = $("label", jObj);
          var jRadio = $(":radio", jObj);
          for (var i = 0; i < jRadio.size(); ++i) {
              items.push(_jRadioLabel(jRadio.get(i), jLabel.get(i)));
          };
      };

      //
      // Creates a modified jQuery Object-Wrapper for the given Radio/Label pair
      // The jQuery radio Object has some added methods and properties:
      //     .radio:          returns the dom-RadioButton Object
      //     .label           returns the jQuery-Label Object
      //     .checked:        gets/sets the checked state of the RadioButton
      //
      function _jRadioLabel(radio, label) {

          var jRadio = $(radio);

          jRadio.radio = radio;
          jRadio.label = $(label);

          if (jRadio.label.size() == 1)
              label.htmlFor = radio.id;

          jRadio.checked = function(bChecked) {
              /// <summary>
              /// gets or sets the checkded state of the RadioButton
              /// </summary>    
              ///    <returns type="boolean">checked state</returns>
              if (arguments.length) {
                  bChecked = (typeof (bChecked) == 'boolean') ? bChecked : true;
                  radio.checked = bChecked; // setter
                  return jRadio;
              };
              return radio.checked;  // getter
          };

          jRadio.enable = function(bEnable) {
              /// <summary>
              /// enable/disable RadioButton and associated Label
              /// </summary>    
              bEnable = (typeof (bEnable) == 'boolean') ? bEnable : true;
              radio.disabled = !bEnable;
              jRadio.label.css("color", bEnable ? "" : "#ccc")
              if (!bEnable) radio.checked = false;
              return jRadio;
          };

          jRadio.disable = function() {
              /// <summary>
              /// diables  RadioButton and associated Label
              /// </summary>    
              return jRadio.enable(false);
          };

          return jRadio;
      };
  };

Using the RadioGroup Control:

jGroup=$("#container").RadioGroup();  // Create extended RadioGroup Object
jGroup.disable(0);                    // disable the first button
jGroup.disable(0,3,4);                // disable a list of radio buttons

jGroup.val("1");                      // Set a value and so select a button
db.IDRadio = jGroup.val().toInt();    // read the radio group into a field ..

jGroup.get(0);                        // returns first button as jQuery object
jGroup.get(1,2);                      // returns Array of two jQuery radio buttons
jGroup.get("checked");                // return selected jQuery radio button

var domRadio = jGroup.get(0).radio;   // access the radio Dom object
var domLabel = jGroup.get(0).label;   // access the label Dom object

Resources:

• The Source Code ( tomsoft.radiogroup.js )
• RadioGroup Live Demo Page

Keywords:		jquery, javascript
Categories:		ASP.NET | JavaScript | jQuery
Advanced:		E-mail | del.icio.us | Permalink | Comments (0) | Comment RSS