jquery attribute selectors

How to Use jQuery Selectors?

jQuery has power of minimizing lines of code. jQuery would be the powerful tool for the DOM. jQuery is easy to select elements using selector engine, it’s easy syntax, which is based on the same syntax you would use to select elements in CSS by borrowing from CSS 1-3. jQuery selects or finds element on page by Element Id, it is jQuery option to getElementById. By using get element by id selector jQuery uses elements Id. Other selector jQuery uses is Get element by class. In this jQuery selector class name of the element is used to access the elements on page. jQuery also get element by attribute. Also by using hierarchy jQurey selects element on page. jQuery has filters that are also useful to get elements.We will see some samples of different types of selectors.

Element by ID

In the example below we will see a selection of an element by id.It is same as java scripts getElementById(). Using the id of element jQuery gets element on the page.It has every easy syntax.

<html>
<head>   
<title>Get Element by ID</title>
<script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js"></script> 
<script type="text/javascript">     
//get element by it's ID   
alert($("#message").text()); // Hello jQuery  
</script>
</head> 
<body>    
<div id="message">Hello jQuery</div>  
</body>  
</html>

jQuery uses the native JavaScript function getElementById(), for id selectors. The fastest way to select an element is to reference it by its id selector.
It’s also important that your id should not contain the special characters like:
#;&,.+*~':"!^$[]()=>|/
The characters above if not properly escaped ay confuse the jQuery selector engine as it is a different type of selector. You can use escape character way like below to handle special characters.

$(“#some:id”) -> $(“#some\\:id”)

Get Elements by its class

In below example we will select all elements on the page that have the specified class name. jQuery uses the class of element and get the element from the page.

<html>  
<head>  
<title>Get Element by class selector</title>  
<script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js"></script>  
<script type="text/javascript">  
//Get  the element by it's classname   
alert($(".message ").text()); // HellojQuery  
</script>  
</head>  
<body>  
<p id="hello">  
<span class="message">Hello</span> <span class="message">jQuery</span>  
</p>  
</body>  
</html>

In above example, selector matched both the span elements that have class= “message” and combined contents into one result ‘HellojQuery’.

jQuery will use the native JavaScript function GetElementsByClassName().

Get Elements by Attribute

Below example shows how to select elements that have an attribute with some specific value.

<html>  
<head>  
<title>Get Element by its attribute</title>  
<script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js"></script>  
<script type="text/javascript">  
//get  elements by its attribute   
alert($("input[name= name]").val()); // johan   
</script>  
</head>  
<body>  
<form>  
<p> Name: <input type="text" name="name"  value="Johan" />  </p>
<p> Phone: <input type="text" name="phone" value="0000000" /> </p>
</form>  
</body>  
</html>

Here selector finds all matching ‘input’ elements then the element that have an attribute of ‘name’ and that also have the value ‘name’.

Get Elements by Hierarchy

Descendent Selector (“parent child”) – This will selects all descendent child elements of the parent including element which may a child, grandchild, great-grandchild, and so on, of that element.

Example:

<p><a href="http://google.com">Google</a></p>  
<div>  
<p> <a href="http://Yahoo.com">Yahoo!</a></p>  
<p><a href="http://gmail.com">Gmail</a></p>  
</div>  
<ul>
<li><a href="http://jquerymobile.com">jQuery Mobile</a></li>
</ul>
<div>
<ul>
<li><a href="http://jquery.com">jQuery</a></li>
<li><a href="http://jqueryui.com">jQuery UI</a></li>
</ul>
</div>

When we write jQuery like:

$("div p");

It will give us below result:

<p> <a href="http://Yahoo.com">Yahoo!</a></p>  
<p><a href="http://gmail.com">Gmail</a></p>

And if we write like below code

$("div ul");

then it’s result will be like:

<ul>
<li><a href="http://jquery.com">jQuery</a></li>
<li><a href="http://jqueryui.com">jQuery UI</a></li>
</ul>

Child Selector (“parent > child”) – This may be used when you need to selects all direct child elements of the parent.
Example:

<p><a href="http://google.com">Google</a></p>  
<div>  
<p> <a href="http://Yahoo.com">Yahoo!</a></p>  
<p><a href="http://gmail.com">Gmail</a></p>  
</div>  
<ul>
<li><a href="http://jquerymobile.com">jQuery Mobile</a></li>
</ul>
<div>
<ul>
<li><a href="http://jquery.com">jQuery</a></li>
<li><a href="http://jqueryui.com">jQuery UI</a></li>
</ul>
</div>

When we write jQuery like:

$("p > a");

This will give us all the <a> tags:

<a href="http://google.com">Google</a>
<a href="http://Yahoo.com">Yahoo!</a></
<a href="http://gmail.com">Gmail</a>

And below code will be resulted as:

$("li > a");

Result of above code will be

<a href="http://jquerymobile.com">jQuery Mobile</a>
<a href="http://jquery.com">jQuery</a>
<a href="http://jqueryui.com">jQuery UI</a>

Get Elements by Filters

<!DOCTYPE html>
<html>
<head>
<title>Select Element by Selector Filter</title>
</head>
<body>
jQuery project sites:
<ul>
<li><a href="http://jquery.com">jQuery</a></li>
<li><a href="http://jqueryui.com">jQuery UI</a></li>
<li><a href="http://sizzlejs.com">Sizzle</a></li>
<li><a href="http://jquery.org">jQuery Project</a></li>
</ul>
<script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js"></script>
<script type="text/javascript">
//Select the element by attribute
alert($("a:first").attr("href")); // http://jquery.com
</script>
</body>
</html>

There are three types of filter selectors that you can used to get elements: numerical or positioned filters, CSS filters and Pseudo filters

Numerical or positioned filters:

:first< matched first Gives –>

:last - Gives last matched element

:first-child – Gives the first child element

:last-child - Gives the last child element

:only-child - Gives all element that have no siblings

:nth-child(n) - Gives the nth child element

:nth-child(even|odd) – Gives the matched even or odd children elements

:nth-child(xn+y) - Gives the nth matched children elements based on some formula.

:even - Gives even children elements

:odd - Gives odd children elements

:eq(n) - Gives nth position child element

:gt(n) - gives the children element those are greater than the nth position

:lt(n) - gives the children element those are less than the nth position

Traditional CSS filters:

:checked – It is basically used with checkboxes or radio buttons. It will return all checked elements.

:disabled – This will return all disabled elements

:enabled – This will give us all enabled elements

jQuery Pseudo filters:

:animated – Gives all elements with animations.

:button – Returns all button elements

:checkbox - Returns all checkbox elements

:contains(string) - Returns the elements those contain given string

Example: $(“div:contains(Google)”)

:file – Return all file input elements

:has(selector) –Returns elements that have at least one of the specified matched selector.

:header - Returns header elements.

:hidden – Returns all hidden elements

:image - Returns image input elements

:input - Returns form elements

:parent - Returns elements that have children, including text, which are not empty

:password - Returns elements of type password

:radio - Returns radio elements

:reset - Returns reset buttons

:selected - Returns option elements in selected state

:submit - Returns elements of type submit

:text - Returns elements of type text

:visible - Returns elements that are visible

gridview add new row

By Avinash

In this post we will see how to add new row to grid. Gridview have a footer template. By default the visibility is false for this footer template . On add new row button click event, we will set the visibility of Gridview footer row to true and bind the grid again.

Aspx code:

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"> 
<Columns> 
<asp:TemplateField HeaderText="ID"> 
<ItemTemplate> 
<asp:Label ID="lblID" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"ID") %>'> 
</ItemTemplate> 
<FooterTemplate> 
 
</FooterTemplate> 

</asp:TemplateField> 
<asp:TemplateField HeaderText="First Name"> 
<ItemTemplate> 
<asp:Label ID="lblfirstName" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"FirstName") %>'> 
</ItemTemplate> 
<FooterTemplate> 
<asp:TextBox ID="txtFirstName" runat="server"> 
</FooterTemplate> 
</asp:TemplateField> 
<asp:TemplateField HeaderText="Last Name"> 
<ItemTemplate> 
<asp:Label ID="lblLastName" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"LastName") %>'> 
</ItemTemplate> 
<FooterTemplate> 
<asp:TextBox ID="txtLastName" runat="server"> 
</FooterTemplate> 
</asp:TemplateField> 
<asp:TemplateField HeaderText="Email"> 
<ItemTemplate> 
<asp:Label ID="lblEmail" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"Email") %>'></asp:Label> 
</ItemTemplate> 
<FooterTemplate> 
<asp:TextBox ID="txtEmail" runat="server"> 
</FooterTemplate> 
</asp:TemplateField> 
<asp:TemplateField HeaderText="Check all"> 
<HeaderTemplate> 
<asp:CheckBox ID="CheckBox2" AutoPostBack="true" runat="server"  OnCheckedChanged="CheckBox2_CheckedChanged1" /> 
</HeaderTemplate> 
<ItemTemplate> 
<asp:CheckBox ID="CheckBox1"  runat="server" /> 
</ItemTemplate> 
<FooterTemplate> 
<asp:LinkButton ID="lnkSave" runat="server" CommandName="Save" OnClick="lnkSave_Click">Save 
</FooterTemplate> 
</asp:TemplateField> 
</Columns> 
</asp:GridView>

C# code behind

using System; 
using System.Data; 
using System.Web; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using System.Web.UI.HtmlControls; 

public partial class _Default : System.Web.UI.Page 
{ 
protected void Page_Load(object sender, EventArgs e) 
{ 
if (!Page.IsPostBack) 
{ 
BindGrid(); 
} 
} 
private void BindGrid() 
{ 
GridView1.DataSource = GridDataProvider.GetData(); 
GridView1.DataBind(); 
} 

protected void CheckBox2_CheckedChanged1(object sender, EventArgs e) 
{ 
foreach (GridViewRow r in GridView1.Rows) 
{ 
((CheckBox)r.FindControl("CheckBox1")).Checked = true; 
} 
} 
protected void Button1_Click(object sender, EventArgs e) 
{ 
} 
protected void Button2_Click(object sender, EventArgs e) 
{ 
GridView1.ShowFooter = true; 
BindGrid(); 
} 
protected void lnkSave_Click(object sender, EventArgs e) 
{ 
string ID = (  (TextBox)  GridView1.FooterRow.FindControl("txtID") ).Text ; 
string firstName = (  (TextBox)  GridView1.FooterRow.FindControl("txtFirstName") ).Text; 
// similarly you can find other controls and save 
}

Vb.Net Code

Imports System 
Imports System.Data 
Imports System.Configuration 
Imports System.Web 
Imports System.Web.Security 
Imports System.Web.UI 
Imports System.Web.UI.WebControls 
Imports System.Web.UI.WebControls.WebParts 
Imports System.Web.UI.HtmlControls 
Public Partial Class _Default 
Inherits System.Web.UI.Page 
Protected Sub Page_Load(sender As Object, e As EventArgs) 
If Not Page.IsPostBack Then 
BindGrid() 
End If 
End Sub 
Private Sub BindGrid() 
GridView1.DataSource = GridDataProvider.GetData() 
GridView1.DataBind() 
End Sub 

Protected Sub CheckBox2_CheckedChanged1(sender As Object, e As EventArgs) 
For Each r As GridViewRow In GridView1.Rows 
(DirectCast(r.FindControl("CheckBox1"), CheckBox)).Checked = True 
Next 
End Sub 
Protected Sub Button1_Click(sender As Object, e As EventArgs) 
End Sub 
Protected Sub Button2_Click(sender As Object, e As EventArgs) 
GridView1.ShowFooter = True 
BindGrid() 
End Sub 
Protected Sub lnkSave_Click(sender As Object, e As EventArgs) 
Dim ID As String = (DirectCast(GridView1.FooterRow.FindControl("txtID"), TextBox)).Text 
Dim firstName As String = (DirectCast(GridView1.FooterRow.FindControl("txtFirstName"), TextBox)).Text 
' similarly you can find other controls and save 
End Sub 
End Class

C# read text file

By Avinash | In C# , csharp

In this post we are going to discuss how to read text file in c#. .Net provides File class in System.IO namespace which contains methods to read file from the disk.
We can read all the contents of text file in one go using ReadAllText() method of File class.
Also we can use ReadAllLines() method of File class and read each line of the file and store it in the string array and then by iterating through string array we can show each line.
System.IO namespace also contains StreamReader class which has ReadLine() method that we can use to read a Text file one line at a time.We will now see code samples to read file in C# by all the ways we discussed above.

Sample code to read text file in one go [C#]

We will use here ReadAllText() method in File class read all the contents of text file as one string [C#]



class ReadFile
{
 static void Main()
 {
   // Example to Read the file as a whole string.
    string fileText =  System.IO.File.ReadAllText( @"C:\MyFolder\TextFile.txt"); 
   // Show read content of text file in text box .
    TextBox1.Text = fileText ;
}
}

Sample code to read text file in line by line in string array [C#]

we will use here to read all lines by line in text file using ReadAlllines() method in File class.



class ReadFileLines
{
 static void Main()
{ 
   // Example to Read the file lines into a string array.
   string[] allLines = System.IO.File.ReadAllLines (@"C:\MyFolder\TextFile.txt"); 
   //Write text file contents to text box
  foreach(string line in allLines)
  {
   TextBox.Text += "\t\n" + line;
  }
 }
}

we will now look how we can use ReadLine() method of StreamReader class to read each line of text file.

Sample code to read each line of text file [C#]



int counter = 0;
string line;

// Read the file and display it line by line.
System.IO.StreamReader file = new System.IO.StreamReader(@"c:\test.txt");
while((line = file.ReadLine()) != null)
{
System.Console.WriteLine (line);
counter++;
}
file.Close();
System.Console.WriteLine("There were {0} lines.", counter);
System.Console.ReadLine();

delete folder, directory c#

By Avinash | In C# , csharp

In order to remove a directory or folder using C#, .Net framework provides System.IO namspace which provides Directory.Delete method.
Directory.Delete is a static method that gives you easy way to delete or remove folder or directory. Also we can delete directory or folder using DirectoryInfo class of System.IO namespace.

Examples of deleting directory or folder Directory.CreateDirectory:

Following is sample code for deleting or removing directory or folder on root i.e. at C:/ drive

using System.IO;

class DeleteFolder
{
static void Main()
{

// Delete Directory/folder on C:\ Drive.
Directory.Delete("C:\\TestDirectory");
}
}

Sample code to delete directory using System.IO DirectoryInfo class

using System.IO;

class CreateNewFolder
{
static void Main()
{

// Get Directory info or folder info.
DirectoryInfo dir = new DirectoryInfo(@"c:\TestDirectory");
dir.Delete();
}
}

Create new folder, directory

By Avinash | In C# , csharp

In this post we will see how to create create folder or directory using C# on server to perform some operations dynamically. .Net provides System.IO namespace to perform operation related to file system. System.IO namespace also provides ways to create new folder or directory.In order to create a directory or new folder using C#, we can either use Directory.CreateDirectory method of the System.IO namespace or we can use DirectoryInfo class of System.IO namespace.

Directory.CreateDirectory is a static method that gives you easy way to create new folder or new directory. we will see example of creating new directory or folder using Directory.CreateDirectory:

Sample code that shows how to create directory or folder on root i.e. at C:/ drive



usingSystem.IO;
class CreateNewFolder
{
 static void Main()
 {
   // Create new Directory or folder on C:\ Drive.
   Directory.CreateDirectory("C:\\TestDirectory");
 }
}

We can also add subfolders to the existing folder, so below C# code shows how to create subdirectory or sub folder in existing folder.



using System.IO;
class CreateNewFolder
{
 static void Main()
 {
   // Create new Directory or folder on C:\ Drive.
   Directory.CreateDirectory("C:\\TestDirectory\\SubFolder");
}
}

There are also alternative ways to create sub directory or sub folders. We can create directory or folder using DirectoryInfo class of System.IO namespace.

Sample code to create directory using System.IO DirectoryInfo class

using System.IO;
    class CreateNewFolder
    {
    static void Main()
    {
    // Get Directory info or folder info.
    DirectoryInfo dir = new DirectoryInfo(@"c:\TestDirectory");
    dir.create();
    }
    }

ASP.Net Authentication Modes

By Avinash | In asp.net

ASP.Net supports below authentication modes:
1. Windows
2. Forms
3. Passport
4. None

To enable authentication provider or mode we need to use authentication element from config file.

<system.web>
   <!-- mode=[Windows|Forms|Passport|None] -->
   <authentication mode="Windows" />
</system.web>

1.Windows:
This is a default authentication mode in asp.net. This uses windows credentials for authentication. It relies on IIS to authenticate the user. Aftre authenticating the user it passes security token to asp.net. Windows authentication provides below ways:

Anonymous: IIS allows everybody to access asp.net application, no authentication is done.

Basic: User must have to provide username and password to get access to application. But username and password get sent over network in plain text format so it is bit insecure.

Digest: Same as Basic windows authentication but password is hashed before sending it over the netwrok and also user need to be use IE5 or later and windows accounts should stored in active directory.

Windows Integrated: User still need to provied username and password but it never sent over the network. Application either uses kerberos or challenge response protocol to authenticate the user. Kerberos provides tools for authentication and strong cryptography for secure communication.

2. Forms Authentication mode: Forms authentication uses own customised HTML form to collect users credentials. Client or user directly sends credentials to asp.net application code for authenticatio. If application authenticates user it issues a cookie to ensure user is present on subsequent requests.

<!-- Web.config file -->
<system.web>
   <authentication mode="Forms">
      <forms forms="demoApp" loginUrl="/login.aspx" />
   </authentication>
</system.web>

3. Passport Authentication: Passport authentication mode provides centralized authentication process provided by microsoft passport service. When user site registered with passport, the passport service grants site specific key.

<!-- Web.config file -->
<system.web>
   <authentication mode="Passport" />
</system.web>

ASP.Net Caching, Caching Concept

By Avinash | In asp.net

ASP.NET Caching:

Caching is process of storing frequently used data for reuse. Generally it stores data in memory becuase accessing data from memory is more efficient way rather that generate it again.

ASP.NET provides two types of catching:
1. Output Caching
2. Application Data Caching

Page Output Caching:
Output caching is done with entire page or with the fragment/part of the page.
a. Page Output Caching: ASP.Net allows caching entire contents of the page. This is good for caching static pages.

<%@ OutputCache Duration="60" VaryByParam="None" %>

Fragement/Pratial Page Caching:
This is same as page output caching, but instead it uses to store part or fragment of the page in cache. This is done by caching user controls (.ascx) used in page.

<%@ OutputCache Duration="300" VaryByParam="*" Shared="true" %>

Here shared="true" is used to share same HTML if the user control is used in more than one pages, and to avoid caching same output/HTML of user control multiple time.

Application Data Caching:

This is used to store data in cache like dataset or any collection objects, or any object that need to be cached:

Item can be added to cache using Cache.Insert(param, param) with expiration parameter. Also Item can be added to cache using Cache.add(param, param) with priority.

Data set can be added to cache like Cache["MyDataSet"] = MyDataSet; and retrived like ds = (DataSet) Cache["MyDataSet"].

C# | ASP.net | jQuery | Javascript | linq

jquery attribute selectors

How to Use jQuery Selectors?

Element by ID

Get Elements by its class

Get Elements by Attribute

Get Elements by Hierarchy

Get Elements by Filters

Numerical or positioned filters:

jQuery Pseudo filters:

gridview add new row

C# read text file

Sample code to read text file in one go [C#]

Sample code to read text file in line by line in string array [C#]

Sample code to read each line of text file [C#]

delete folder, directory c#

Examples of deleting directory or folder Directory.CreateDirectory:

Sample code to delete directory using System.IO DirectoryInfo class

Create new folder, directory

Sample code that shows how to create directory or folder on root i.e. at C:/ drive

Sample code to create directory using System.IO DirectoryInfo class

ASP.Net Authentication Modes

ASP.Net Caching, Caching Concept

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