C# as

The as manipulator is like a cast operation. Still, if the conversion is not possible, as returns zero rather of raising an exception.

as operator only executes reference transitions and boxing transitions. The as operator cannot execute other transitions, such as user-defined transitions, which should rather be executed by using cast reflections.

Example :

class ClassA { }
class ClassB { }

class MainClass
{
    static void Main()
    {
        object[] objArray = new object[6];
        objArray[0] = new ClassA();
        objArray[1] = new ClassB();
        objArray[2] = "hello";
        objArray[3] = 123;
        objArray[4] = 123.4;
        objArray[5] = null;

        for (int i = 0; i < objArray.Length; ++i)
        {
            string s = objArray[i] as string;
            Console.Write("{0}:", i);
            if (s != null)
            {
                Console.WriteLine("'" + s + "'");
            }
            else
            {
                Console.WriteLine("not a string");
            }
        }
    }
}

/*

Output:

0:not a string
1:not a string
2:'hello'
3:not a string
4:not a string
5:not a string
*/