Var role in C # with C ++, the auto, the type automatically infer local variable by a compiler can reduce the code, for example:
VeryComplicatedType X = new new VeryComplicatedType ();
not good code, as VeryComplicatedType rewritable twice, above the sentence should be changed to:
var = the X-new new VeryComplicatedType ();
appropriate use var, not only can make the code look cleaner, and sometimes can also increase the flexibility of the code, third-party libraries such as data type is changed, it is possible to own code You do not need to synchronize changes.
var only two purposes:
- Var can be used when typing less declare variables, especially in the generic type declaration of a nested variable.
- When referring to objects stored anonymous type must be used, because they can not know in advance the type name, for example: var foo = new {Bar = "bar"};
var only local variable type may be used, can not be declared var domain, attribute, parameter or return type.
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