可能是重复问题:
C#中作用域问题
在C#中,似乎在if/else/loop块的本地作用域中定义的变量与该块后面定义的变量发生冲突 - 请参见代码片段。在C/C++和Java中,等效的代码可以编译通过。这是C#中预期的行为吗?
public void f(){
if (true) {
/* local if scope */
int a = 1;
System.Console.WriteLine(a);
} else {
/* does not conflict with local from the same if/else */
int a = 2;
System.Console.WriteLine(a);
}
if (true) {
/* does not conflict with local from the different if */
int a = 3;
System.Console.WriteLine(a);
}
/* doing this:
* int a = 5;
* results in: Error 1 A local variable named 'a' cannot be declared in this scope
* because it would give a different meaning to 'a', which is already used in a
* 'child' scope to denote something else
* Which suggests (IMHO incorrectly) that variable 'a' is visible in this scope
*/
/* doing this:
* System.Console.WriteLine(a);
* results in: Error 1 The name 'a' does not exist in the current context..
* Which correctly indicates that variable 'a' is not visible in this scope
*/
}