What is the advantage of using var self = this in knockout view models?
Partial methods enable the implementer of one part of a class to define a method, similar to an event. The implementer of the other part of the class can decide whether to implement the method or not. If the method is not implemented, then the compiler removes the method signature and all calls to the method. The calls to the method, including any results that would occur from evaluation of arguments in the calls, have no effect at run time. Therefore, any code in the partial class can freely use a partial method, even if the implementation is not supplied. No compile-time or run-time errors will result if the method is called but not implemented.
- All partial-type definitions meant to be parts of the same type must be modified with partial. For example, the following class declarations generate an error:
- The partial modifier can only appear immediately before the keywords class, struct, or interface.
- Nested partial types are allowed in partial-type definitions as illustrated in the following example:
- All partial-type definitions meant to be parts of the same type must be defined in the same assembly and the same module (.exe or .dll file). Partial definitions cannot span multiple modules.
- The class name and generic-type parameters must match on all partial-type definitions. Generic types can be partial. Each partial declaration must use the same parameter names in the same order.
- The following keywords on a partial-type definition are optional, but if present on one partial-type definition, cannot conflict with the keywords specified on another partial definition for the same type:
- base class
- new modifier (nested parts)
- generic constraints
- An extension method will never be called if it has the same signature as a method defined in the type.
- Extension methods are brought into scope at the namespace level. For example, if you have multiple static classes that contain extension methods in a single namespace named Extensions, they will all be brought into scope by the using Extensions; directive.
- Implement Finalize only on objects that require finalization. There are performance costs associated with Finalize methods.
- If you require a Finalize method, consider implementing IDisposable to allow users of your class to avoid the cost of invoking the Finalize method.
- Do not make the Finalize method more visible. It should be protected, not public.
- An object's Finalize method should free any external resources that the object owns. Moreover, a Finalize method should release only resources that the object has held onto. The Finalize method should not reference any other objects.
- Do not directly call a Finalize method on an object other than the object's base class. This is not a valid operation in the C# programming language.
- Call the base class's Finalize method from an object's Finalize method.
- Implement the dispose design pattern on a type that encapsulates resources that explicitly need to be freed. Users can free external resources by calling the public Dispose method.
- Implement the dispose design pattern on a base type that commonly has derived types that hold onto resources, even if the base type does not. If the base type has a Close method, often this indicates the need to implement Dispose. In such cases, do not implement a Finalize method on the base type.Finalize should be implemented in any derived types that introduce resources that require cleanup.
- Free any disposable resources a type owns in its Dispose method.
- After Dispose has been called on an instance, prevent the Finalize method from running by calling the GC.SuppressFinalize. The exception to this rule is the rare situation in which work must be done in Finalize that is not covered by Dispose.
- Call the base class's Dispose method if it implements IDisposable.
- Do not assume that Dispose will be called. Unmanaged resources owned by a type should also be released in a Finalize method in the event thatDispose is not called.
- Throw an ObjectDisposedException from instance methods on this type (other than Dispose) when resources are already disposed. This rule does not apply to the Dispose method because it should be callable multiple times without throwing an exception.
- Propagate the calls to Dispose through the hierarchy of base types. The Dispose method should free all resources held by this object and any object owned by this object. For example, you can create an object such as a TextReader that holds onto a Stream and an Encoding, both of which are created by the TextReader without the user's knowledge. Furthermore, both the Stream and the Encoding can acquire external resources. When you call theDispose method on the TextReader, it should in turn call Dispose on the Stream and the Encoding, causing them to release their external resources.
- Consider not allowing an object to be usable after its Dispose method has been called. Re-creating an object that has already been disposed is a difficult pattern to implement.
- Allow a Dispose method to be called more than once without throwing an exception. The method should do nothing after the first call.