问题

我想这样做。

```rust
#[repr(u8)]
pub enum MessageType {
    认证,
    // ...
}
fn main() {
  let message_type = MessageType::认证;
  let binary_representation: u8 = message_type.into();
}

我觉得我不得不手动实现 into。

有没有人有一个可以使用这个表示来转换我的类型的解决方案。

我觉得可以在不安全的情况下做到，但我宁愿不这样做。

这仍然可能对文化有趣。

<details>
<summary>英文:</summary>

I would like to do that.

#[repr(u8)]
pub enum MessageType {
Authentification,
// ...
}
fn main() {
let message_type = MessageType::Authentification;
let binary_representation: u8 = message_type.into();
}

I see myself obliged to implement into by hand.

Does anyone have a solution that would use the representation to convert my type.

I think it's possible to do it in unsafe, but I'd rather not.

It could still be interesting for culture.

</details>


# 答案1
**得分**: 2

你需要手动定义每个变体的值，并在转换时使用 `as` 而不是 `.into()`，因为 `Into<u8>` 没有由 `MessageType` 实现：

```rust
#[repr(u8)]
pub enum MessageType {
    Authentication = 1,
    // ...
}

fn main() {
    let n = MessageType::Authentication as u8;
    println!("{}", n);
}

#[repr(u8)]
pub enum MessageType {
    Authentication = 1,
    // ...
}

fn main() {
    let n = MessageType::Authentication as u8;
    println!("{}", n);
}