The lock statement

The lock statement

The lock statement obtains the mutual-exclusion lock for a given object, executes a statement, and then releases the lock.

lock-statement:
lock ( expression ) embedded-statement

The expression of a lock statement must denote a value of a reference-type. An implicit boxing conversion (‎6.1.5) is never performed for the expression of a lock statement, and thus it is an error for the expression to denote a value of a value-type.

A lock statement of the form

lock (x)

where x is an expression of a reference-type, is precisely equivalent to

System.Threading.Monitor.Enter(x);
try
finally

except that x is only evaluated once. The Enter and Exit methods of the System.Threading.Monitor class are described in the CLR specification.

The System.Type object of a class can conveniently be used as the mutual-exclusion lock for static methods of the class. For example:

class Cache

}

public static void Remove(object x)
}
}