What are the differences between const and readonly ?

Differences between const and readonly

Sno	const	readonly
1	Can't be static.	Can be instance level or static
2	evaluated at design time	evaluated at run time
3	Initialized at declaration	Initialized at declaration and in constructor
4	must be of integral type or enumeration	In addition it can have complex types with new keyword and enumerations are not allowed

 

How can you tell the application to look for assemblies at the locations other than its installed location?

You can do that by adding the following entry in the web.config file,


<probing privatePath="c:\yourlibrary; bin\debug" />

How to read and write from a text file using c#.net ?

See the following sample,

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace ReadWriteFromTxt
{
class Program
{
static void readFile()
{
FileStream fsEmp = new FileStream("c:\\Emp.html", FileMode.Open, FileAccess.Read);
StreamReader srEmp = new StreamReader(fsEmp);
string s;
while ((s = srEmp.ReadLine()) != null)
{
Console.WriteLine(s);
Console.Read();
}
srEmp.Close();
fsEmp.Close();
}

static void writeFile()
{
FileStream fsEmp = new FileStream("c:\\Emp.html", FileMode.Open, FileAccess.Write );
StreamWriter swEmp = new StreamWriter(fsEmp );

string s="Have you seen god? Is there anything else to see";
swEmp.WriteLine(s);
swEmp.Close();
fsEmp.Close();

}


static void Main(string[] args)
{
writeFile();
readFile();
}
}
}

How to download webpage using asp.net and c# ?

See the following code,

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Net;

namespace DownloadingFile
{
class Program
{
static void Main(string[] args)
{
WebRequest reqFile = WebRequest.Create("http://www.codecollege.net/2009/07/cloud-computing.html");

WebResponse resFile = reqFile.GetResponse();

Stream smFile = resFile.GetResponseStream();
// Output the downloaded stream to the console
StreamReader sr = new StreamReader(smFile);
string line;
while ((line = sr.ReadLine()) != null)
Console.WriteLine(line);
Console.Read();
}
}
}

What’s the difference between authentication and authorization?

what is Authentication?


Is a process by which the system decides whether the user is valid to login to the site as a whole.


what is Authorization?


Is a process by which the system decides which are the areas and functionalities the user is allowed to access, at the component level.

How to read and write from a text file using c#.net ?

See the following sample,

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace ReadWriteFromTxt
{
class Program
{
static void readFile()
{
FileStream fsEmp = new FileStream("c:\\Emp.html", FileMode.Open, FileAccess.Read);
StreamReader srEmp = new StreamReader(fsEmp);
string s;
while ((s = srEmp.ReadLine()) != null)
{
Console.WriteLine(s);
Console.Read();
}
srEmp.Close();
fsEmp.Close();
}

static void writeFile()
{
FileStream fsEmp = new FileStream("c:\\Emp.html", FileMode.Open, FileAccess.Write );
StreamWriter swEmp = new StreamWriter(fsEmp );

string s="Have you seen god? Is there anything else to see";
swEmp.WriteLine(s);
swEmp.Close();
fsEmp.Close();

}


static void Main(string[] args)
{
writeFile();
readFile();
}
}
}

what are the Differences between Abstract Class and Interface ?

Difference between Abstract Class and Interface

Sno	Abstract Class	Interface
1	Can have implemented Methods	Cant
2	A class can inherit only one abstract class	A Class can implement any number of Interfaces.
3	We go for Abstract classes on such situations where we need to give common functionality for group of related classes	We go for Interface on such situations where we need to give common functionality for group of un-related classes
4	If you add a new method, then you can provide a default implementation and so no need to make any change to existing work.	If you add a new method, then you need to change all the existing work.
5	Static and Instance constants are possible.	Only Static  constants are possible.