Define Implicit and Explicit Operator - C# Tips

C# allow us to define Implicit and Explicit operators. Unlike casting Implicit and Explicit operators defines how C# should behave when encountering a equals sign.

Implicit operator execution can be invoke when assigning a variable or calling a method.

To use Explicit operator we should do the same as casting an object. It's similar to a cast an object.

public record class Email(string Value)
{
    //define implicit operator
    public static implicit operator string(Email value) 
      => value.Value;

    //define implicit operator
    public static implicit operator byte[](Email value) 
      => Encoding.UTF8.GetBytes(value.Value);

    //define explict operator
    public static explicit operator Email(string value) 
      => new Email(value);
}

Define custom operators on Record Class

To define a implicit/explicit we need to make use of "operator", "implicit" or "explicit" keywords.

The following example demonstrate the use of both operators.

Email email = new("rmauro@rmauro.dev");

//use implicit operator. This is not a cast
string stringEmail = email;

Email secondEmail = (Email)stringEmail;

//output rmauro@rmauro.dev
System.Console.WriteLine(stringEmail); 
System.Console.WriteLine(secondEmail.Value.ToString());

Making use of defined Operators

The explicit conversion is similar to a cast operation. We make visible the type to which we will convert the object. The implicit operator is less visible and difficult to understand if you don’t know it exists.