Type Conversion

Remarks#

Type conversion is converting one type of data to another type. It is also known as Type Casting. In C#, type casting has two forms:

Implicit type conversion - These conversions are performed by C# in a type-safe manner. For example, are conversions from smaller to larger integral types and conversions from derived classes to base classes.

Explicit type conversion - These conversions are done explicitly by users using the pre-defined functions. Explicit conversions require a cast operator.

MSDN implicit operator example

class Digit
{
    public Digit(double d) { val = d; }
    public double val;

    // User-defined conversion from Digit to double
    public static implicit operator double(Digit d)
    {
        Console.WriteLine("Digit to double implict conversion called");
        return d.val;
    }
    //  User-defined conversion from double to Digit
    public static implicit operator Digit(double d)
    {
        Console.WriteLine("double to Digit implict conversion called");
        return new Digit(d);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Digit dig = new Digit(7);
        //This call invokes the implicit "double" operator
        double num = dig;
        //This call invokes the implicit "Digit" operator
        Digit dig2 = 12;
        Console.WriteLine("num = {0} dig2 = {1}", num, dig2.val);
        Console.ReadLine();
    }
}

Output:

Digit to double implict conversion called
double to Digit implict conversion called
num = 7 dig2 = 12

Live Demo on .NET Fiddle

Explicit Type Conversion

using System;
namespace TypeConversionApplication 
{
   class ExplicitConversion 
   {
      static void Main(string[] args) 
      {
         double d = 5673.74; 
         int i;
         
         // cast double to int.
         i = (int)d;
         Console.WriteLine(i);
         Console.ReadKey();
      }
   }
}