The as Operator

The as operator works like a cast, except that if it can’t perform the indicated conversion, it returns null (a null reference that does not refer to any object) rather than throwing an exception as an unsuccessful explicit conversion would.

For example, the following code snippet will store a null reference in the variable str (with the resulting display that “i is not a string”):

object i = 42;
string str = i as string;
if (str == null){
MessageBox.Show("i is not a string", "as demo")
}
else {
MessageBox.Show(str, "as demo");
}

Had the variable i contained string data, such as

then the string data “hello” would have been displayed in the message box after the object type i was converted to the string type str.

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