Data Reader In ADO.NET

using System;
using System.Data.SqlClient;

class Program
{
static void Main()
{
SqlConnection con=new SqlConnection();
con.ConnectionString="server=.;database=student;integrated security=true;";
SqlCommand cmd=new SqlCommand();
cmd.Connection=con;
cmd.CommandText="SELECT * FROM student";
SqlDataReader reader;
con.Open();
reader=cmd.ExecuteReader();

Console.WriteLine("Sno\tSname\t\tCourse\tDuration");
Console.WriteLine("-------------------------------------------------------------------");
while(reader.Read())
{
Console.WriteLine("{0}\t{1}\t{2}\t{3}",reader["Sno"],reader["Sname"],reader["Cname"],reader["duration"]);
Console.WriteLine();
}
reader.Close();
con.Close();
}
}

DataBase Connectivity in c#

using System;
using System.Data.SqlClient;

class Program
{
static void Main()
{
SqlConnection con=new SqlConnection();
SqlCommand cmd=new SqlCommand();
int n;
string command;

con.ConnectionString="server=.;database=Student;integrated security=true;";
cmd.Connection=con;

// command="CREATE TABLE student(Sno INT PRIMARY KEY IDENTITY(1,1),Sname VARCHAR(30),Cname VARCHAR(30),Duration INT)";
// cmd.CommandText=command;

// con.Open();
// Console.WriteLine("Connected to Sql Server");
// cmd.ExecuteReader();
// Console.WriteLine("Table Created Successfully");
// con.Close();

command="INSERT INTO student(Sname,Cname,Duration) VALUES ('SMRITI DABGAR','.NET',90)";
cmd.CommandText=command;

con.Open();
n=cmd.ExecuteNonQuery();
Console.WriteLine("{0} Records Inserted Successfully",n);
con.Close();

command="DELETE FROM student WHERE sno=1";
cmd.CommandText=command;

con.Open();
n=cmd.ExecuteNonQuery();
Console.WriteLine("{0} Records Deleted Successfully",n);
con.Close();

command="UPDATE student SET sname='ANKUR BHATNAGAR' WHERE sno=2";
cmd.CommandText=command;

con.Open();
n=cmd.ExecuteNonQuery();
Console.WriteLine("{0} Records Updated Successfully",n);
con.Close();

command="SELECT count(*) FROM student WHERE Cname='.NET'";
cmd.CommandText=command;

con.Open();
object ob=cmd.ExecuteScalar();
Console.WriteLine("Total No Of Records in .NET is: {0}",(int)ob);
con.Close();
}
}

StringBuilder in C#

//String classs and StringBuilder Class Comparision
using System;
using System.Text;
class Program
{
static void Main()
{
StringBuilder sb=new StringBuilder();

Console.WriteLine("\n......................String Builder Example......................\n");

sb.Append("This is a example of string");

Console.WriteLine("\nActual String is: '{0}'",sb.ToString());

sb.Replace("string","StringBuilder");
Console.WriteLine("\nAfter Replace String is: '{0}'",sb.ToString());

sb.Insert(0,"Extra ");
Console.WriteLine("\nAfter Insert String is: '{0}'",sb.ToString());

sb.Remove(0,5);
Console.WriteLine("\nAfter Remove String is: '{0}'",sb.ToString());

Console.WriteLine("\nStart Time: {0}",DateTime.Now.ToString("T"));
for(int i=0;i<100000;i++)
sb.Append(i);
Console.WriteLine("\nEnd Time: {0}",DateTime.Now.ToString("T"));

Console.WriteLine("\n......................String Example......................\n");
string s1="";

Console.WriteLine("\nStart Time: {0}",DateTime.Now.ToString("T"));
for(int i=0;i<100000;i++)
s1=s1+i;
Console.WriteLine("\nEnd Time: {0}",DateTime.Now.ToString("T"));
}
}

String Funtions in C#

// Program to demonstrate sting funtions
//Instance level funtions: ToUpper(), ToLower(), Trim(), Split(), IndexOf(), LastIndexOf(), Substing(), Contains
//Static Funtions: Concat()
using System;
class Program
{
static void Main()
{
string s1,s2;
s1="Hello";
s2="World";

s1=string.Concat(s1,s2);
Console.WriteLine("Cancat Result: {0}",s1);

Console.WriteLine("Upper Result: {0}",s1.ToUpper());
Console.WriteLine("Lower Result: {0}",s1.ToLower());

bool b=s1.Contains("World");
Console.WriteLine("Contains Result: {0}",b);

int n=s1.IndexOf("llo");
Console.WriteLine("IndexOF Result: {0}",n);

n=s1.LastIndexOf('l');
Console.WriteLine("LastIndexOf Result: {0}",n);

Console.WriteLine("Substring Result: {0}",s1.Substring(3));
Console.WriteLine("substring Result: {0}",s1.Substring(3,5));

s2="                    Ankur Bhatnagar                    ";
Console.WriteLine("Before Trim Result: {0}",s2.Length);
s2=s2.Trim();
Console.WriteLine("After Trim Result: {0}",s2.Length);

s2="ASP.NET,C#.NET,VB.NET";
string[] str=s2.Split(',');
Console.WriteLine("Split Result:");
foreach(string item in str)
{
Console.WriteLine("{0}",item);
}
}
}

Exception Handling in c#

//Program to handle exception using try catch finally
using System;
class Program
{
static void Main()
{
int x,y,z=0;

try
{
Console.Write("Enter X: ");
x=int.Parse(Console.ReadLine());
Console.WriteLine();

Console.Write("Enter Y: ");
y=int.Parse(Console.ReadLine());
Console.WriteLine();

z=x/y;
}
catch(Exception exp) //It is called as Most General Exception.It can handle all the exception because it is a top most pareant of all other exceptions
//class.So accourding to 'Run Time Polymorphism' Parent class contains the object of their children.
{
Console.WriteLine(exp.Message);
}
finally
{
Console.WriteLine("Result: {0}",z);
}
}
}

Multiple Catch Blocks

//Program to handle exception using try Multiple catch finally
using System;
class Program
{
static void Main()
{
int x,y,z=0;
try
{
Console.Write("Enter X: ");
x=int.Parse(Console.ReadLine());
Console.WriteLine();

Console.Write("Enter Y: ");
y=int.Parse(Console.ReadLine());
Console.WriteLine();

z=x/y;
}

catch(FormatException exp) //Called Specific Exception.Handles Only Exceptions Related to FormatException
{
Console.WriteLine("X and Y Both Must be Integer Type");
}

catch(DivideByZeroException exp) //Called Specific Exception.Handles Only Exceptions Related to DivideByZeroException
{
Console.WriteLine("You should not divide by 0");
}

catch(Exception exp) //Handles all Other Exceptions because it is known as General Exception.This must be at end of all exception Defined
//Why because it can handle all exception.So it must be at end of all Specific Exception.
{
Console.WriteLine(exp.Message);
}
finally
{
Console.WriteLine("Result: {0}",z);
}
}
}

Throwing Exception

//Program to throwing Exception Manually
using System;
class Program
{
static void Main()
{
int age=0;
try
{
Console.Write("Enter Age: ");
age=int.Parse(Console.ReadLine());
Console.WriteLine();

if(age<=0)
//throw is a keyword in c#.Net used to throw an exception.
throw new FormatException("Age Can not be less Than equal to zero");

if(age>100)
throw new FormatException("Invalid Range Of Age");
}
catch(Exception exp)
{
Console.WriteLine(exp.Message);
}
finally
{
Console.WriteLine("Entered Age: {0}",age);
}
}
}

Stack in C#

//Stack demonstration
using System;
using System.Collections;

class Program
{
static void Main()
{
Stack stackObj=new Stack();

stackObj.Push(20);
stackObj.Push(30);
stackObj.Push(50);
stackObj.Push(40);
stackObj.Push(60);
stackObj.Push(80);

//To Print Stack Objects
Console.WriteLine();
foreach(object obj in stackObj)
{
Console.WriteLine((int)obj);
}
Console.WriteLine();

for(int i=0;i<stackObj.Count;i=i+0)
{
Console.WriteLine((int)stackObj.Pop());
}
}
}

Generate Random no List

//Program to store 20 Random no in List and find sum of them.
using System;
using System.Collections.Generic;

class Program
{
static void Main()
{
Random rdm=new Random(); // Random class is there in system namespace used to generate random numbers
List<int> lst=new List<int>();

for(int i=0;i<20;i++)
{
int n=rdm.Next(0,300); // Next Is a instance method of Random class used to generate Next Random no with in the specified Range.
lst.Add(n);
}

int sum=0;
Console.WriteLine();
foreach(int n in lst)
{
Console.Write("{0} ",n);
sum+=n;
}
Console.WriteLine("\n");
Console.WriteLine("Sum: {0}",sum);
}
}

Generic Queue

//Generic Queue demonstration
using System;
using System.Collections.Generic;

class Program
{
static void Main()
{
Queue<int> queueObj=new Queue<int>();

queueObj.Enqueue(20);
queueObj.Enqueue(30);
queueObj.Enqueue(50);
queueObj.Enqueue(40);
queueObj.Enqueue(60);
queueObj.Enqueue(80);

for(int i=0;i<queueObj.Count;i=i+0)
{
Console.WriteLine(queueObj.Dequeue());
}
}
}

Queue in c#

//demonstration of Queue Class
using System;
using System.Collections;

class Customer
{
private int no;
private string name,request;

public Customer(int id)
{
no=id;
}

public int Id
{
get
{
return no;
}
}

public string Name
{
get
{
return name;
}
set
{
name=value;
}
}

public string Requestinfo
{
get
{
return request;
}
set
{
request=value;
}
}

}
class Program
{
static void Main()
{
Queue customerDetailsQueue=new Queue();

Customer c;

c=new Customer(1001);
c.Name="Ankur Bhatnagar";
c.Requestinfo="Network problem";
customerDetailsQueue.Enqueue(c);

c=new Customer(1002);
c.Name="Ankit Agarwal";
c.Requestinfo="Desktop problem";
customerDetailsQueue.Enqueue(c);

c=new Customer(1003);
c.Name="Tushar Agarwal";
c.Requestinfo="Mouse problem";
customerDetailsQueue.Enqueue(c);

//To print Queue Items
foreach (object obj in customerDetailsQueue)
        {
Console.WriteLine("Id: {0}, Name: {1},Request: {2}", ((Customer)obj).Id, ((Customer)obj).Name, ((Customer)obj).Requestinfo);
        }

Console.WriteLine();

for(int i=0;i<customerDetailsQueue.Count;)
{
Customer obj= (Customer)customerDetailsQueue.Dequeue();
Console.WriteLine("Id: {0} Name: {1} Problem:{2}",obj.Id,obj.Name,obj.Requestinfo);
}
}
}

Generic Stack

//Generic Stack demonstration
using System;
using System.Collections.Generic;

class Program
{
static void Main()
{
Stack<int> stackObj=new Stack<int>();

stackObj.Push(20);
stackObj.Push(30);
stackObj.Push(50);
stackObj.Push(40);
stackObj.Push(60);
stackObj.Push(80);

for(int i=0;i<stackObj.Count;i=i+0)
{
Console.WriteLine(stackObj.Pop());
}
}
}

Generic List Collection

//Generic List Demonstration
using System;
using System.Collections.Generic;

class Program
{
static void Main()
{
List<string> list=new List<string>();

list.Add("ASP.NET");
list.Add("C#.NET");
list.Add("VB.NET");
list.Add("Java");
list.Add("Jquery");

PrintList(list);

Console.WriteLine("\nAfter using Insert Statement list is:");
list.Insert(0,"JavaScript");
PrintList(list);

Console.WriteLine("\nAfter using Remove Statement list is:");
list.Remove("JavaScript");
PrintList(list);

Console.WriteLine("\nAfter using Remove At Statement list is:");
list.RemoveAt(1);
PrintList(list);
}

static void PrintList(List<string> list)
{
Console.WriteLine();
foreach(string s in list)
{
Console.Write("{0} ",s);
}
Console.WriteLine();
}

}

Generic sortedList Collection

// Create a Generic contact list of your friends using Generic Sorted List
using System;
using System.Collections.Generic;

class Program
{
static void Main()
{
SortedList<string,string> ContactList=new SortedList<string,string>();

//Adding Names and address of your friend in contact list
ContactList.Add("Smriti Dabgar","Bareilly");
ContactList.Add("Ankur Bhatnagar","Hyderabad");

foreach(string key in ContactList.Keys)
{
Console.WriteLine("{0} Lives In {1}",key,ContactList[key]);
}
}
}

Creating SortedList

// Create a contact list of your friends using Sorted List
using System;
using System.Collections;

class Program
{
static void Main()
{
SortedList ContactList=new SortedList();

//Adding Names and address of your friend in contact list
ContactList.Add("Ankur Bhatnagar","Hyderabad");
ContactList.Add("Smriti Dabgar","Bareilly");


foreach(object key in ContactList.Keys)
{
Console.WriteLine("{0} Lives In {1}",key,ContactList[key]);
}
}
}

SortedList Collection class

//Program of sortedList Of Departments
using System;
using System.Collections;

class Program
{
static void Main()
{
SortedList deptList=new SortedList();

//Adding elements to sorted List
deptList.Add(20,"Sales");
deptList.Add(40,"Admin");
deptList.Add(10,"IT");
deptList.Add(30,"purchase");
deptList.Add(50,"Finance");

//Processing SortedList
foreach(object key in deptList.Keys)
{
string s=(string)deptList[key];
Console.WriteLine("Key: {0}, Value: {1}",key,s);
}
}
}

ArrayList in C#

//to demonstrate ArrayList Class
using System;
using System.Collections;

class Program
{
public static void Main()
{
ArrayList arr=new ArrayList();
arr.Add("ASP.NET");
arr.Add("C#");
arr.Add("SQL SERVER");
arr.Add("ADO.NET");
arr.Add("JAVA SCRIPT");
arr.Add("JQUERY");

Console.WriteLine("Actual Array");
PrintList(arr);

Console.WriteLine("After adding Element Array is");
arr.Add("VB.NET");
PrintList(arr);

Console.WriteLine("After Inserting Element Array at First Position is");
arr.Insert(0,".NET TECHNOLOGY");
PrintList(arr);

Console.WriteLine("After Removing Element Array JQUERY is");
arr.Remove("JQUERY");
PrintList(arr);


Console.WriteLine("After Removing Element Array at First Position is");
arr.RemoveAt(0);
PrintList(arr);

Console.WriteLine("After Clearing Element Array ");
arr.Clear();
PrintList(arr);
}

public static void PrintList(ArrayList arr)
{
string str;
Console.WriteLine("\n");
foreach(object obj in arr)
{
str=(string)obj;
Console.Write(str+"  ");
}
Console.WriteLine("\n");
}
}

Method Arguments and Parameters

using System;
class ParamTest
{
//call by value
public  void Update(int a)
{
a=a+10;
}

//call by Reference
public  void Swap(ref int a,ref int b)
{
int t=a;
a=b;
b=t;
}

//call by Out
public  void Power(int a,out int b,out int c)
{
b=a*a;
c=a*a*a;
}
}

class Program
{
public static void Main()
{
ParamTest obj=new ParamTest();

int x=10,a=10,b=20,y,z;
Console.WriteLine("Before Update x={0}",x);
obj.Update(x);
Console.WriteLine("After Update x={0}",x);

Console.WriteLine("Before Swapping a={0} and b={1}",a,b);
obj.Swap(ref a,ref b);
Console.WriteLine("Before Swapping a={0} and b={1}",a,b);

x=5;
obj.Power(x,out y,out z);
Console.WriteLine("X:{0}, Y={1} Z={2}",x,y,z);
}
}

Boxing and Unboxing in c#

//Program to Demonstrate Boxing And Unboxing
using System;
class Program
{
static void Main()
{
int i=123; // Value Type

object obj=i;// Implicit Boxing

int j=(int)obj;// Explicit/ Unboxing

//string s=(string)obj;//Note: This Statement will Give System.InvalidCastException
//why because object is boxed an int value while we r trying to convert it in to string

Console.WriteLine(j);
}
}

DateTime Structure In C#

// Program to demonstrate DateTime
using System;

class Program
{
static void Main()
{
DateTime d=DateTime.Now;

//To Print Only Date
Console.WriteLine("------------Date Only------------");
Console.WriteLine(d.ToString("d"));
Console.WriteLine(d.ToString("D"));


//To Print Only Time
Console.WriteLine("------------Time Only------------");
Console.WriteLine(d.ToString("t"));
Console.WriteLine(d.ToString("T"));

//To Print Only Day
Console.WriteLine("------------Day Only------------");
Console.WriteLine(d.ToString("dd"));
Console.WriteLine(d.ToString("ddd"));
Console.WriteLine(d.ToString("dddd"));

//To Print Only Month
Console.WriteLine("------------Month Only------------");
Console.WriteLine(d.ToString("M"));
Console.WriteLine(d.ToString("MM"));
Console.WriteLine(d.ToString("MMM"));
Console.WriteLine(d.ToString("MMMM"));

//To Print Only Year
Console.WriteLine("------------Year Only------------");
Console.WriteLine(d.ToString("YYYY"));
Console.WriteLine(d.ToString("YY"));

//To Print Only hours
Console.WriteLine("------------Hours Only------------");
//Console.WriteLine(d.ToString("H"));
Console.WriteLine(d.ToString("HH"));

//To Print Only Minutes
Console.WriteLine("------------Minutes Only------------");
Console.WriteLine(d.ToString("m"));
Console.WriteLine(d.ToString("mm"));

//To Print Only Seconds
Console.WriteLine("------------Seconds Only------------");
Console.WriteLine(d.ToString("s"));
Console.WriteLine(d.ToString("ss"));

//To Print Diffrent Cobinations of Date Time
Console.WriteLine("------------Combinations of above formats------------");
Console.WriteLine(d.ToString("ddd dd-MM-YYYY"));
Console.WriteLine(d.ToString("dddd, dd MMMM YYYY hh:mm:ss"));
}
}