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Possible Duplicate:
Why is this code invalid in C#?
Conditional operator cannot cast implicitly?
如果我执行以下操作:
bool someBool = false;
uint value = 0;
这些都很好:
value = (someBool) ? 0 : (uint)1;
value = (someBool) ? (uint)0 : 1;
但这不是:
value = (someBool) ? 0 : 1;
当我可以轻松地说时，为什么我不能使用最后一个:
value = 0;
value = 1;
三元运算符的类型是如何确定的？
最佳答案
您必须将其转换为 uint 以便编译器知道。 0 和 1 都可以是 uint 或 int。
这是语言规范(可以从 MSDN here 下载):
The second and third operands of the ?: operator control the type of the conditional expression. Let X and Y be the types of the second and third operands. Then,
If X and Y are the same type, then this is the type of the conditional expression.
Otherwise, if an implicit conversion exists from X to Y, but not from Y to X, then Y is the type of the conditional expression.
Otherwise, if an implicit conversion exists from Y to X, but not from X to Y, then X is the type of the conditional expression.
Otherwise, no expression type can be determined, and a compile-time error occurs.
关于c# - 我可以从三元运算中得到什么类型？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11040100/