int myInt = 10;
float myFloat = myInt;

string myString = "Hello World";object myObject = myString;  // Implicit conversion
// Perform an explicit conversionstring myString2 = (string)myObject;

object myObject = "Hello World";
string myString = myObject is string ? (string)myObject : null;

object[] array = new object[] { 1, "two", 3.3 };
 // i的值為1  int? i = array[0] as int?;
// s的值為"two"  string s = array[1] as string; 
// j的值為null，因為3.3不能轉(zhuǎn)換為int，但不會引發(fā)異常int? j = array[2] as int?;

object[] array = new object[] {3};
//as寫法，代碼簡單易懂int? num1 = array[0] as int?;if (num1 != null){    Console.WriteLine(num1); //輸出 3}
//傳統(tǒng)寫法，代碼冗長int? num2 = null;try{    num2 = (int?)array[0];}catch{    num2 = null;}if (num2 != null){    Console.WriteLine(num2);  //輸出 3}