错误 [E0412]：在此 scope 中找不到类型 `String`

Question

#![cfg_attr(not(feature = "std"), no_std)]

use ink_lang as ink;

#[ink::contract]

mod XYZ {

    #[ink(storage)]
    pub struct Xyz {
        token_id: u32,
        serial_code: String
    }
    ...
}

错误：

             serial_code: String
   |                      ^^^^^^ not found in this scope

Answer 1

基于此——你应该使用ink!中包含的String类型！

use ink_prelude::string::String;

并包含在正确的 Cargo.toml 文件中：

[Dependencies]
ink_prelude = { version = "2", git = "github.com/paritytech/ink", tag = "latest-v2", package = "ink_prelude", default-features = false }"

（或任何适合您的版本）