difference between viewbag and viewdata and tempdata in mvc3

the main difference below,

ViewData:

• ViewData is a dictionary of objects that is derived from ViewDataDictionary class and accessible using strings as keys

• It’s required type casting for complex data type and check for null values to avoid error.

ViewBag: 

• ViewBag doesn’t require typecasting for complex data type.
• ViewBag is a dynamic property that takes advantage of the new dynamic features in C# 4.0. 

Check the following example:

public class HomeController : Controller

{

    public ActionResult Index()

    {

        var emp = new Employee

        {

            EmpID=101,

            Name = "Deepak",

            Salary = 35000,

            Address = "Delhi"

        };

        ViewData["emp"] = emp;

        ViewBag.Employee = emp;

        return View(); 

    }

}

And the code for View is as follows:

@model MyProject.Models.EmpModel;

@{ 

 Layout = "~/Views/Shared/_Layout.cshtml"; 

 ViewBag.Title = "Welcome to Home Page";

 var viewDataEmployee = ViewData["emp"] as Employee; //need type casting

}

<h2>Welcome to Home Page</h2>

This Year Best Employee is!

<h4>@ViewBag.emp.Name</h4>

<h3>@ViewData.Employee.Name</h3>

javascript == and === difference

1. === operater
=== means value must be equal and type as well
Ex:
var value1=1;
var value2='1';

if(value1===value2) /// this will return false because this value type is different(javascript will do internal type casting even though if we use === it will follow the strict rules),

and

if(0===false) // this will return false because different data type


2.== operator

== means value must be equal,

Ex:
var value1=1;
var value2='1';
if(value1==value2) /// this will return true because (==) will check only value(javascript handle type conversion).

and
if(0==false) // this will return true because false is equal to 0

Best 100+ Frequently Asked Interview Questions in .Net SQL

refer this link

http://www.webblogsforyou.com/100-frequently-asked-interview-questions-on-asp-net-sql-server-oop-concepts/

cannot open backup device operating system error 5(access is denied.)

possible reason for this errors are,

1. there is no directory with the name
ex, if u r mention path as 'D:\test\abc.bak' may be this directory wont be there or not access for your credentials.
2.second possible is, u wont be having enough space in the disk to save the data.
3.you may not having enough permission/rights in logs drive
ex, if your mention a folder name, for that folder u might not having write permission, something like that.

how to take database backup using sql query

in query window use this syntex:

backup datsbase databasename to disk='location to store'


Example:

backup database sureshdatabase in disk = 'D:\sureshDBBackup\sureshdatabase.bak'

after forming this query execute.

pass new empty model to partial view

follow this
@Html.RenderPartial("ViewPath", new ModelName());

view path Ex: "Views//Child/childview.cshtml"

assign null value to enum in c#

You can use the "?" operator for a enum nullable type.

Ex:

public enumname? objenum = null;

or else u can create one more enum as none then use it.