????27.  ????????????????????????
????//????
????public enum Color  : long
????{
????Red??Green??Blue
????}
????28.  ???if?????????????if???????????????????????
????29.  ??????????????????????
????30.  ??????????????е??÷???bool??????????????t?????????????Щ?????????
????bool IsEverythingOK()
????{…}
????//????
????if (IsEverythingOK ())
????{…}
????//?滻????
????bool ok = IsEverythingOK();
????if (ok)
????{…}
????31.  ??????????0????????顣
????32.  ????????????????????????????????顣
????public class MyClass
????{}
????MyClass[] array = new  MyClass[100];
????for(int index = 0; index < array.Length;  index++)
????{
????array[index] = new  MyClass();
????}
????33.  ?????public ?? protected?????????????????????????
????34.  ?????????????new?????override?滻??
????35.  ?????sealed???????????public ?? protected?????????virtual???
????36.  ???????interop(COM+ ????????dll)??????????ò?????????(unsafe code)??
????37.  ?????????????????as?????????м?????????????
????Dog dog = new GermanShepherd();
????GermanShepherd shepherd = dog  as  GermanShepherd;
????if (shepherd != null )
????{…}
????38.  ????????????е????
????a)  Copy a delegate to a local variable before publishing to avoid concurrency race
????condition.
????b)  ???????????????????????null
public class MySource
{
public event EventHandler  MyEvent;
public void FireEvent()
{
EventHandler temp = MyEvent;
if(temp != null )
{
temp(this??EventArgs.Empty);
}
}
}
????39.  ????????????????????????????????????滻??Щ??????
public class MySource
{
MyDelegate m_SomeEvent ;
public event MyDelegate SomeEvent
{
add
{
m_SomeEvent += value;
}
remove
{
m_SomeEvent -= value;
}
}
}