Modify DOM using jQuery contextMenu and dialog

Introduction
Recently we got a requirement to modify document object model with jQuery context menu  plugin. We could achieve this very easily with jQuery context menu plugin and jQuery dialog.

Details goes here-
For ease let us take a list of divs with some margin, padding and background color. The HTML for this goes here-

    <style>
        div.enableCtx
        {
            width:200px;
            background-color: Gray;
            margin: 5px 5px 5px 5px;
            padding: 5px 5px 5px 5px;
            color:White;
            font-size:15px;
        }
    </style>

    <div class="enableCtx"> data 1</div>
    <div class="enableCtx"> data 2</div>
    <div class="enableCtx"> data 3</div>
    <div class="enableCtx"> data 4</div>
    <div class="enableCtx"> data 5</div>
    <div class="enableCtx"> data 6</div>
    <div class="enableCtx"> data 7</div>
    <div class="enableCtx"> data 8</div>
    <div class="enableCtx"> data 9</div>

The requirement that we are going to implement here is as follows-

• Use context menu jQuery plugin for this
• The context menu should have options for add, edit and delete.
• For adding and editing the data in each div we are going to use jQuery dialog.
• The add functionality will add a similar div with with the added content next to the current div. 

Now to use contextMenu, we need the necessary JavaScript and CSS files. In this case we can use the following references-

    <script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.7.js" type="text/javascript"></script>

    <script src="http://labs.abeautifulsite.net/archived/jquery-contextMenu/demo/jquery.contextMenu.js"
        type="text/javascript"></script>

    <link href="http://labs.abeautifulsite.net/archived/jquery-contextMenu/demo/jquery.contextMenu.css"
        rel="stylesheet" type="text/css" />

Next we need to create UI for context menu. And it goes like below-

    <ul id="myMenu" class="contextMenu">
        <li class="copy"><a href="#Add">Add</a></li>
        <li class="edit"><a href="#Edit">Edit</a></li>
        <li class="delete"><a href="#Delete">Delete</a></li>
        <li class="quit separator"><a href="#Cancel">Cancel</a></li>
    </ul>

Now we can enable context menu by calling the following JavaScript-

        $(document).ready(function() {
            EnableContext();
        });
        function EnableContext() {
            $("div.enableCtx").contextMenu({
                menu: 'myMenu'
            },
            function(action, el, pos) {
            });
        }

If we notice we can check that the contextMenu takes a function as a second parameter with three attributes called action, el and pos. action stands for what option we have selected from the menu potion. In this case these can be Add, Edit, Delete and Cancel. The value of this is taken from the href value except #. el stands for target element, in our case its one of the div we are right clicking. And the last parameter pos is the coordinate position of the mouse click.

Now what we can do is write a function for each of the operation with exactly the same name as in action and use eval for evaluating the function call. The code goes here-

     <script type="text/javascript">
        $(document).ready(function() {
            EnableContext();
        });
        function EnableContext() {
            $("div.enableCtx").contextMenu({
                menu: 'myMenu'
            },
            function(action, el, pos) {
                eval(action + "(el)");
            });
        }

        function Add(el) {
            //add implementation
        }
        function Edit(el) {
            //edit implementation
        }
        function Delete(el) {
            //delete implementation
        }
        function Cancel(el) {
            //cancel implementation
        }
     </script>

Here is the beauty of eval function. Suppose we have selected Add option from the context menu then it will evaluate the statement Add(el). That means its going to call the add function. Similarly for others.

Next comes the actual implementation of the functions. As we have decided to use jQuery dialog for add and edit purpose. So, we need to setup dialog. Here we are going to take dialog as a div with a text box for editing the content of the selected div. The dialog references and HTML goes here-

     <script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.9/jquery-ui.js" type="text/javascript"></script>
     <link href="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.9/themes/redmond/jquery-ui.css" rel="stylesheet" type="text/css" />

    <div style="display:none" id="dialog" title="Add content">
        Enter Text: <nput type="text" id="text" />
   </div>

Add function-

   
        function Add(el) {
            $("#text").val("");
            $("#dialog").dialog({
                model: true,
                buttons: {
                    add: function() {
                        el.after($("<div>").addClass("enableCtx").html($("#text").val()));
                        EnableContext();
                        $(this).dialog("close");
                    }
                }
            });
        }

What we are doing in the add function is setting the textbox inside the dialog to empty, opening the dialog with a button called add. And in the add button click handler we are creating a dynamic div with class enableCtx and adding the content of the div as the textbox value. We are then adding the dynamic div next to the current div(el). We are recalling the EnableContext() function to add the same context behavior to the added div. And finally closing the dialog.

Edit, delete and cancel functions-

 
        function Edit(el) {
            $("#text").val(el.html());
            $("#dialog").dialog({
                model: true,
                buttons: {
                    Edit: function() {
                        el.html($("#text").val());
                        $(this).dialog("close");
                    }
                }
            });
        }
        function Delete(el) {
            el.remove();
        }
        function Cancel(el) {
        }

Edit function is simple, we are first copying the div HTML to textbox inside dialog, replacing the current div(el) HTML with textbox changed value. and closing the dialog.

Delete function is simply removing the current div. And in case of cancel function we need to to implement anything as it will automatically close the context menu.

Source code is here.

Restricting to floating point number onkeypress

Very simple JavaScript code to restrict text box to have floating point number. Code is here-

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
 <title>Untitled Page</title>
 <script type="text/javascript">
     function restrict(val, e) {
         var keyChar;
         if (window.event)
             keyChar = String.fromCharCode(window.event.keyCode);
         else if (e)
             keyChar = String.fromCharCode(e.which);
         else
             return true;
         var number = parseFloat(val + keyChar);
         if (number != val + keyChar)
             return false;
         else
             return true;
     }
</script>
</head>
<body>
 <input name="number" onkeypress="return restrict(this.value, event)">
</body>
</html>

JSON to HTML table

There was a need to converting JSON object to HTML Table. I found out different solutions over internet. But there was no generic solution where I can pass a JSON string and get the HTML table in return. So, I tried out a solution with JavaScript. The code is as follows-

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
   <title>Untitled Page</title>
</head>
<body>
   <form id="form1"  runat="form1">
   <div id="test">
   </div>
   <script type="text/javascript">
       var table = "[{'Country':'mycity','Name':'abc','Age':'29','Email':'test@mail.com'}," +
               "{'Name':'abcd','Age':'39','Email':'test1@mail.com'}," +
               "{'Name':'abcde','Age':'30','Email':'test2@mail.com'}," +
               "{'Age':'30','Sex':'male','Name':'abcde'}]";
       table = eval('' + table + '');
       var tableObject = function (json) {
           var headerCount = new Object();
           var createTR = function (id) {
               var tr = document.createElement("tr");
               tr.ID = id;
               return tr;
           };
           var createTH = function (html) {
               var th = document.createElement("th");
               th.innerHTML = html;
               return th;
           };
           var createTD = function (html) {
               var td = document.createElement("td");
               td.innerHTML = html;
               return td;
           };
           var getName = function (id) {
               for (var name in headerCount) {
                   if (eval("headerCount." + name) == id) {
                       return name;
                   }
               }
           };
           var pTable;
           if (json.length > 0) {
               var index = 0;
               pTable = document.createElement("table");
               var head = createTR();
               for (var i = 0; i < json.length; i++)
                   for (var item in json[i]) {
                       if (!headerCount.hasOwnProperty(item)) {
                           head.appendChild(createTH(item));
                           eval('headerCount.' + item + "=" + index);
                           index++;
                       }
                   }
               pTable.appendChild(head);
               for (var i = 0; i < json.length; i++) {
                   var row = new createTR(i);
                   for (var j = 0; j < index; j++) {
                       var name = getName(j);
                       if (eval("json[" + i + "].hasOwnProperty('" + name + "')")) {
                           row.appendChild(createTD(eval('json[' + i + '].' + name)));
                       }
                       else
                           row.appendChild(createTD(''));
                   }
                   pTable.appendChild(row);
               }
           }
           return pTable;

       };
       var c = new tableObject(table);
       document.getElementById("test").appendChild(c);
</script>
   </form>
</body>
</html>

HTML MULTI SELECT - maintain multiple selection state without Control Key.

Problem Description:
Recently I had a problem with MULTISELECT. The default behavior of MULTISELECT is that when we need to select multiple items at a time, either we need to press control key and then by mouse click select multiple item or by mouse drag. My problem was to maintain the previously selected item without the help control key.

Solution:
A simple jQuery code serves this purpose as follows



I have used ID selector. But we can use any kind of selector of our choice.

Implementing UNION with LINQ to Entity

This post uses LINQ to Entity and Set Methods - UNION to select rows from different tables in the database.

What To Do
I have five database tables named Exhibitors, ExhibitorContacts, ExhibitorVessels, ExhibitorDrylands, ExhibitorServices.

An exhibitor(Exhibitors) can have multiple contacts(ExhibitorContacts). A contact can have multiple entries in Vessel(ExhibitorVessels), Dry land(ExhibitorDrylands) or Services(ExhibitorServices).

Now i need to find out all the distinct contacts that have some items in the last three tables.

LINQ to Entity Code is

var cv = (from ev in bts.ExhibitorVessels
                where ev.Exhibitors.ExhibitorID == 3
                 select new { ContactID = ev.ExhibitorContacts.ContactID }
               )
               .Union(
               from ed in bts.ExhibitorDrylands
               where ed.Exhibitors.ExhibitorID == 3
               select new { ContactID = ed.ExhibitorContacts.ContactID}
               )
               .Union(
               from es in bts.ExhibitorServices
               where es.Exhibitors.ExhibitorID == 3
               select new { ContactID = es.ExhibitorContacts.ContactID }
               );

Here bts is my Entity object.

Bind ArrayList Text and Value Field to DataList

Description:
Here is the code for binding the text and the value fields of the ArrayList to a DataList in Asp.net using C#.

HTML:
<asp:DataList ID="DataList1" runat="server">
<ItemTemplate>
<%# ((ListItem)Container.DataItem).Text %> ..........<%# ((ListItem)Container.DataItem).Value %>
</ItemTemplate>
</asp:DataList>

Code behind:
ArrayList aa = new ArrayList();
aa.Add(new ListItem("John", "1"));
aa.Add(new ListItem("Smit", "2"));
aa.Add(new ListItem("Bob", "3"));
DataList1.DataSource = aa;
DataList1.DataBind();