C# .NET - What is Casting in C#

Hi All,

  I am a newbie to C#.

 i want to know what exactly is Casting in C#,Please expalin in layman's terms or provide me a good link so that i can study that.

Thanks,

Arth

Converting between data types can be done explicitly using a cast, but in some cases, implicit conversions are allowed.
For example:

static void TestCasting()
{
    int i = 10;
    float f = 0;
    f = i;  // An implicit conversion, no data will be lost.
    f = 0.5F;
    i = (int)f;  // An explicit conversion. Information will be lost.
}
 

A cast explicitly invokes the conversion operator from one type to another. The cast will fail if no such conversion operator is defined.
You can write custom conversion operators to convert between user-defined types. For more information about defining a conversion operator,
see explicit (C# Reference) and implicit (C# Reference).

Example ::

The following program casts a double to an int. The program will not compile without the cast.

class Test
{
    static void Main()
    {
        double x = 1234.7;
        int a;
        a = (int)x;  // cast double to int
        System.Console.WriteLine(a);
    }
}

See this for further understanding :: http://msdn.microsoft.com/en-us/library/ms173105(VS.80).aspx

Hope it helps.

static void TestCasting()
{
    int i = 10;
    float f = 0;
    f = i;  // An implicit conversion, no data will be lost.
    f = 0.5F;
    i = (int)f;  // An explicit conversion. Information will be lost.
}

Go through this l;ink:
http://www.developernotes.com/post/Casting-in-C.aspx
http://msdn.microsoft.com/en-us/library/ms173105(VS.80).aspx

Hi,

Casting is refered as conversion among different data types.

There are two types of casting

1. Implicit conversion

2. Explicitn conversion

check here for more details

http://msdn.microsoft.com/en-us/library/ms173105(VS.80).aspx

Casting means conversion from one datatype to other datatype.

object o = 20;

int x = (int)o;

Here, o is the object having integer value. We need to convert it into integer. So, we need to give (int) i.e. typecast it.

Converting between data types can be done explicitly using a cast, but in some cases, implicit conversions are allowed. For example:

static void TestCasting()
{
    int i = 10;
    float f = 0;
    f = i;  // An implicit conversion, no data will be lost.
    f = 0.5F;
    i = (int)f;  // An explicit conversion. Information will be lost.
}
A cast explicitly invokes the conversion operator from one type to another. The cast will fail if no such conversion operator is defined. You can write custom conversion operators to convert between user-defined types. For more information about defining a conversion operator

class Test
{
    static void Main()
    {
        double x = 1234.7;
        int a;
        a = (int)x;  // cast double to int
        System.Console.WriteLine(a);
    }
}

Output: 1234

Casting is nothing but ability to convert one data type to other type which can be done

For example if a string variable contains 123 as its value, it can be converted to integer type and this can be casted...

on the other hand if the same string variable contians 123str then it can not be converted to integer type...

And there are different ways of casting..

1) Implicit casting

2) Explicit casting

depending on the options of the compiler some languages converts automatically and those are implicit ..

There are 2 types of casting. 
1. C-Style casting
2. Casting using "as" keyword

The most obvious difference is that a C style case will throw and exception if the cast fails 
and the "as" style cast will simply return null.  So first you need to take into consideration 
what these differences will have on your code.  Will you need to wrap every cast in try/catch blocks?  
Not if you use the "as" style, but you will need to check for null.

The best thing is to read http://msdn.microsoft.com/en-us/library/ms173105.aspx where all the types of casting has been given.

Regards,

Paresh