implicit keyword (C# Conversion Keywords)

An implicit keyword is used to declare an implicit user-defined type conversion operator. It is used to enable implicit (automatic) conversions between a user-defined type and another type, if the conversion is guaranteed not to cause a loss of data.

Implicit conversions can improve source code readability by eliminating unnecessary casts. Care must be taken to prevent unexpected results because implicit conversions do not require programmers to explicitly cast from one type to the other. In general, implicit conversion operators should never throw exceptions and never lose information so that they can be used safely without the programmer's awareness. If a conversion operator cannot meet those criteria, it should be marked explicit.

Example:

class Digit

{

public Digit(double dValue) { dVal = dValue; }

public double dVal;

// User-defined conversion from Digit to double

public static implicit operator double(Digit oDigit)

{

return oDigit.dVal;

}

// User-defined conversion from double to Digit

public static implicit operator Digit(double dDoubleVal)

{

return new Digit(dDoubleVal);

}

}

class Program

{

static void Main(string[] args)

{

Digit oDigit = new Digit(7);

double dNum = oDigit; //This call invokes the implicit "double" operator

Digit oDigit2 = 12; //This call invokes the implicit "Digit" operator

Console.WriteLine("dNum = {0} oDigit2 = {1}", dNum, oDigit2.dVal);

Console.ReadLine();

}

}