C# code to write data into text file and to read from text file

The below code is useful to write data into text file and to read from the text file.

using System;

using System.IO;

namespace LearnDataTypes

{   

    class Program

    {

        static void Main(string[] args)

        {

            //Writing into file using C# Code

            StreamWriter sw = new StreamWriter("C:\\Notes.txt");

            sw.WriteLine("Hi, I am writing from CSharp code into file");

            sw.Close();

 

            //Reading from a file using C# Code

            StreamReader sr = new StreamReader("C:\\Notes.txt");

            Console.WriteLine(sr.ReadToEnd());

            sr.Close();

 

            //What about the below code

            //while(!sr.EndOfStream)

            //{

            //    Console.Write(Convert.ToChar(sr.Read()));

            //}

            Console.ReadLine();

        }

    }

}

Hope this will be useful.

Happy Coding.

Cheers,

Meganadha Reddy K.

Difference between Value type and Reference type

Hi All,
Please find below the pictorial difference between value type and reference type:

Hope this will be useful.
Happy coding.

Cheers,
Meganadha Reddy K.

Differences between Class and Structure in C#

Differences between Class and Structure in C#:

I always wanted to know the difference between class and struct.
I am pretty clear now and hope after reading this you will also be clear.
If you find some more differences please add the same as comments.

Sl.No.	Class	Struct
1	Reference Type	Value Type
2	Can assign null to object	Cannot assign null to object
3	Copying one object to other object will copy the memory location. [Refer the below example code]	Copying one object to other will just create a new copy of the existing object. [Refer the below example code]
4	Inheritance is allowed	Inheritance is not allowed for structs
5	We can initialize the class variables to the value we need.	We cannot initialize the struct members. For Example: struct Marks {     public int Percentage=100;            } ** This will throw an error.

 

Class Example [for Sl. No. 3 above for Class Column]

using System; namespace LearnDataTypes {        class Program     {         class Marks         {             public int Percentage;                    }         static void Main(string[] args)         {                        Marks m1 = new Marks();             m1.Percentage = 80;                        Marks m2 = m1;             m1.Percentage += 1;             m2.Percentage += 2;             Console.WriteLine(“m1.Percentage = ” + m1.Percentage +                                     “;m2.Percentage = ” + m2.Percentage);             Console.ReadLine();                    }     } }

Output: m1.Percentage = 83; m2.Percentage = 83

 

Struct Example [for Sl. No. 3 above for Struct Column]

using System; namespace LearnDataTypes {        class Program     {         struct Marks         {             public int Percentage;                    }         static void Main(string[] args)         {                        Marks m1 = new Marks();             m1.Percentage = 80;                        Marks m2 = m1;             m1.Percentage += 1;             m2.Percentage += 2;             Console.WriteLine(“m1.Percentage = ” + m1.Percentage +                                     ”;m2.Percentage = ” + m2.Percentage);             Console.ReadLine();                    }     } }

Output: m1.Percentage = 81; m2.Percentage = 82

 

Hope this will be helpful.

Happy Coding.

Cheers,

Meganadha Reddy K.

Data Types in C# (Contd…)

FCL Name	Data Type	Bytes	Range	Purpose
Char	char	2		Unicode Character
Boolean	bool	1		True/False Values
DataTime	DateTime	8	1/1/0001 to 12/31/9999	To store date time

These are all value types where the value will be directly stored in stack.

Hope this will be useful.

Happy Coding.

Cheers,

Meganadha Reddy K.

Data Types in C# Language – For Storing Numerical Values

Befor learning any programming language, it is verymuch important to know what are all the datatypes available and how efficiently we can use the same. Proper use of the datatypes will certainly improve the performance of the appliacation as well.

C# Data Types:

FCL Name	Data Type	Bytes	Range	Purpose
SByte	sbyte	1	-128 to 127
Byte	byte	1	0 to 255
Int16	short	2	-32768 to 32767
Int32	int	4
UInt32	uint	4
Int64	long	8
UInt64	ulong	8
Single	float	4		Floating point numbers
Double	double	8		Large Floating point numbers
Decimal	decimal	16		Numbers which need highest precision.

 

C# Console application code to check the same:

using System;
namespace LearnDataTypes
{
///
/// Program to print the size and Range of all C# Datatypes.
/// Author : Meganadha Reddy K., Date: 11-October-2010
///
class Program
{
static void Main(string[] args)
{
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}","sbyte",sizeof(sbyte),sbyte.MaxValue,sbyte.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "byte", sizeof(byte), byte.MaxValue, byte.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "short", sizeof(short), short.MaxValue, short.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "int", sizeof(int), int.MaxValue, int.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "uint", sizeof(uint), uint.MaxValue, uint.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "long", sizeof(long), long.MaxValue, long.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "ulong", sizeof(ulong), ulong.MaxValue, ulong.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "float", sizeof(float), float.MaxValue, float.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "double", sizeof(double), double.MaxValue, double.MinValue);
Console.WriteLine("sizeof({0}):{1} Bytes,\t MaxValue: {2}\tMinValue: {3}", "decimal", sizeof(decimal), decimal.MaxValue, decimal.MinValue);
Console.ReadLine();
}
}
}

Output:

C# DataTypes : Program Output

Other available datatypes will be available in next post.

Hope this will be useful to someone.

Happy coding.

Cheers,

Meganadha Reddy K.

ASP.NET Login Control button event on press of Enter key

ASP.NET Login Control button event on press of Enter key:

If we have only login control in our home page then it’s well and good that on enter key press the button click event of login control will be fired and the things will be fine for you.

If we have multiple buttons and one of them is in ASP.NET Login View [For example your page may have “Admin” button at the top right corner and Login Control in middle of page]. Now, when we press enter key after entering password in login control, “Admin” button click event will be fired (which we don’t want to happen). This article will help you how to add Login Control button to be fired one press of Enter key.

So, this article will help you in adding ASP.NET Login View button event when you press Enter Key:

Add the below code in Page_Load() of .aspx.cs page:

if (!this.IsPostBack)
{
//This code will help you to find the Id of the Button in Login Control.
Control myLoginButton = MyLogin.FindControl("LoginButton");
if (myLoginButton != null && myLoginButton is IButtonControl)
MyLogin.Attributes.Add("onKeyPress", doClick('"+ myLoginButton.ClientID+"',event)");
}


Note that, here MyLogin is the Id of your ASP.NET Login Control

Add the below code in <head> section of .aspx page:

function doClick(buttonName, e) {
var key;
if (window.event)
key = window.event.keyCode; //IE
else
key = e.which; //firefox
if (key == 13) {
var btn = document.getElementById(buttonName);
if (btn != null) { //If we find the button click it
btn.click();
event.keyCode = 0
}
}
}

The same can be used for normal button as well; this post will help you to do it for ASP.NET Login Control.

Hope this will be helpful to someone.
Happy Coding.

Cheers,
Meganadha Reddy K.

C# 4.0 Langauge Specification

Dear All,

Microsoft released the final version of .Net Framework 4.0 in April 2010.
You can Click here to download C# 4.0 Language Specification.
This is official microsoft C# 4.0 Language Specification.

Happy Learning.

Cheers,
Meganadha Reddy K.