HTTP is a stateless protocol; it can't hold the user information on web page. If user inserts some information, and move to the next page, that data will be lost and user would not able to retrieve the information. For accessing that information we have to store information. Session provides that facility to store information on server memory. It can support any type of object to store. For every user Session data store separately means session is user specific.
Storing the data in Session object.
Session [“message”] = “Hello World!”;
Retreving the data from Session object.
Label1.Text = Session[“message”].ToString();
What are the Advantages and Disadvantages of Session?
Following are the basic advantages and disadvantages of using session.
Advantages:
- It stores user states and data to all over the application.
- Easy mechanism to implement and we can store any kind of object.
- Stores every user data separately.
- Session is secure and transparent from user because session object is stored on the server.
Disadvantages:
- Performance overhead in case of large number of user, because of session data stored in server memory.
- Overhead involved in serializing and De-Serializing session Data. Because In case of StateServer and SQLServer session mode we need to serialize the object before store.
Describe the Master Page.
Master pages in ASP.NET works as a template that you can reference this page in all other content pages. Master pages enable you to define the look and feel of all the pages in your site in a single location. If you have done changes in master page, then the changes will reflect in all the web pages that reference master pages. When users request the content pages, they merge with the master page to produce output that combines the layout of the master page with the content from the content page.
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ContentPlaceHolder control is available only on master page. You can use more than one ContentPlaceHolder control in master page. To create regions that content pages can fill in, you need to define ContentPlaceHolder controls in master page as follows:
<asp:ContentPlaceHolder ID=”ContentPlaceHolder1” runat=”server”>
</asp:ContentPlaceHolder>
The page-specific content is then put inside a Content control that points to the relevant
ContentPlaceHolder:
<asp:Content ID=”Content1” ContentPlaceHolderID=”ContentPlaceHolder1” Runat=”Server”>
</asp:Content>
Note that the ContentPlaceHolderID attribute of the Content control points to the ContentPlaceHolder that is defined in the master page.
The master page is identified by a special @ Master directive that replaces the @ Page directive that is used for ordinary .aspx pages.
<%@ Master Language="C#" AutoEventWireup="true" CodeFile="CareerRide.master.cs" Inherits="CareerRide" %>
How you can access the Properties and Controls of Master Pages from content pages?
You can access the Properties and Controls of Master Pages from content pages. In many situations you need User’s Name in different content pages. You can set this value inside the master page and then make it available to content pages as a property of the master page.
We will follow the following steps to reference the properties of master page from content pages.
Step: 1
Create a property in the master page code-behind file.
public String UserName
{
get {
return (String)Session["Name"];
}
set {
Session ["Name"] = value;
}
}
Step: 2
Add the @ MasterTypedeclaration to the .aspx content page to reference master properties in a content page. This declaration is added just below the @ Page declaration as follows:
<%@ Page Title=" TEST" Language="C#" MasterPageFile="~/CareerRide.master" AutoEventWireup="true" CodeFile="CareerRideWelcome.aspx.cs" Inherits="CareerRideWelcome" %>
<%@ MasterTypeVirtualPath="~/CareerRide.master" %>
Step: 3
Once you add the @ MasterType declaration, you can reference properties in the master page using the Master class. For example take a label control that id is ID="Label1"
Label1.Text= Master.UserName ;
For referencing controls in the Master Page we will write the following code.
Content Page Code.
protected void Button1_Click(object sender, EventArgs e)
{
TextBox txtName= (TextBox)Master.FindControl("TextBox1");
Label1.Text=txtName.Text;
}
To reference controls in a master page, call Master.FindControl from the content page.
What are the different method of navigation in ASP.NET?
Page navigation means moving from one page to another page in your web site and another. There are many ways to navigate from one page to another in ASP.NET.
- Client-side navigation
- Cross-page posting
- Client-side browser redirect
- Client-Side Navigation
Client-side navigation:
Client-side navigation allows the user to navigate from one page to another by using client side code or HTML. It requests a new Web page in response to a client-side event, such as clicking a hyperlink or executing JavaScript as part of a button click.
Example:
Drag a HyperLink control on the form and set the NavigateUrl property to the desired destination page.
HyperLinkControl: Source
<asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl="~/Welcome.aspx"> Take a test from CareerRide </asp:HyperLink>
Suppose that, this control is placed on a Web page called CareerRide.aspx, and the HyperLink control is clicked, the browser simply requests the Welcome.aspx page.
Second method of client-side navigation is through JavaScript.
Example:
Take an HTML button control on web page. Following is the HTML code for the input button.
<input id="Button1" type="button" value="Go to next page" onclick="return Button1_onclick()" />
When the Button1 is clicked, the client-side method, Button1_onclick will be called. The JavaScript source for the Button1_onclick method is as follows:
<script language="javascript" type="text/javascript">
function Button1_onclick()
{
document.location="NavigateTest2.aspx";
}
</script>
Cross-page posting:
Example:
Suppose that we have two pages, the first page is FirstPage.aspx and Second page is SecondPage.aspx. The First Page has a Button and TextBox control and its ID is Button1 and TextBox1 respectively. A Button control has its PostBackUrl property. Set this property to “~/SecondPage.aspx”. When the user clicks on Button, the data will send to SecondPage for processing. The code for SecondPage is as follows:
protected void Page_Load(object sender, EventArgs e)
{
if(Page.PreviousPage == null)
{
Label1.Text = "No previous page in post";
}
else
{
Label1.Text = ((TextBox)PreviousPage.FindControl("TextBox1")).Text;
}
}
The second page contains a Label control and its ID is Label1.
The page that receives the PostBack receives the posted data from the firstpage for processing. We can consider this page as the processing page.The processing page often needs to access data that was contained inside the initial page that collected the data and delivered the PostBack. The previous page’s data is available inside the Page.PreviousPage property. This property is only set if a cross-page post occurs.
Client-side browser redirect:
The Page.Response object contains the Redirect method that can be used in your server-side code to instruct the browser to initiate a request for another Web page. The redirect is not a PostBack. It is similar to the user clicking a hyperlink on a Web page.
Example:
protected void Button1_Click(object sender, EventArgs e)
{
Response.Redirect ("Welcome.aspx");
}
In client-side browser redirect method an extra round trip to the server is happened.
Server-side transfer:
In this technique Server.Transfer method is used. The Transfer method transfers the entire context of a Web page over to another page. The page that receives the transfer generates the response back to the user’s browser. In this mechanism the user’s Internet address in his browser does not show the result of the transfer. The user’s address bar still reflects the name of the originally requested page.
protected void Button1_Click(object sender, EventArgs e)
{
Server.Transfer("MyPage.aspx", false);
}
The Transfer method has an overload that accepts a Boolean parameter called preserve-Form. You set this parameter to indicate if you want to keep the form and query string data.
