C# 5.0 Programmer's Reference

Events ❘ 775
To create a destructor, create a method named after the class with a ~ character in front of it. For
example, the following code shows a destructor for the Person class.
~Person()
{
// Free unmanaged resources here.
...
}
To allow a program to free resources before an object is destroyed, you can give the class a Dispose
method and implement the IDisposable interface.
The following list summarizes the key destruction issues.
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The destructor is called automatically when an object is destroyed.
The destructor cannot refer to managed objects because they may have already been
destroyed. In particular, the destructor cannot free managed resources because they may
have already been destroyed.
The destructor must free unmanaged resources. This is the last chance the object has for
freeing those resources.
Instead of making the program wait an unknowable amount of time for the destructor to
execute, you can provide a Dispose method that disposes of all resources when the object
is done with them.
If you implement the IDisposable interface, the using statement calls Dispose automatically.
Either it must be safe for the Dispose method and the destructor to both run, or you can
ensure that they both can’t run by making the Dispose method call GC.SuppressFinalize.
Events
An event lets an object notify the application that something potentially interesting has occurred.
Following is the syntax for declaring an event.
«attributes» «accessibility» «new|virtual|override|abstract|sealed» «static»
event delegate name;
The following list describes the declaration’s pieces.
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attributes—Attributes provide extra information about the event for use by the compiler,
the runtime system, and other tools.
accessibility—This can be public, private, protected, internal, or protected
internal and is similar to the accessibility for other items such as classes, properties, and
methods.
new|virtual|override|abstract|sealed—These are similar to the keywords used by
methods described in Chapter 6, “Methods.” They have the following meanings:
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