Question

Can anyone please explain to me what happens behind the scenes when you use ternary operator?
does this line of code:

string str = 1 == 1 ? "abc" : "def";

is generated as a simple if / else statement?
Consider the following:

class A
{
}

class B : A
{
}

class C : A
{
}

Now using ternary expression as follows:

A a1 = 1 == 1 ? new B() : new C();

this doesn’t even compile with this error:

Type of conditional expression cannot be determined because there is no implicit conversion between ‘ConsoleApp1.B’ and ‘ConsoleApp2.C’

Can anyone shed light on this one?

Answer 1

The conditional operator will effectively use the type of the first expression for the second according to whether there is a conversion – and doesn’t take into account bases (otherwise it would just always go to object allowing this: ? "hello" : 10).

In this case, the compiler is correct – there is no conversion between the two types. Add a cast, however on the first one – and it’ll compile – (A)new B().