How to Use Async Traits with Dynamic Dispatch

Async
2026-04-17T12:05:42+00:00
Use the `dyn` keyword with a pointer type like `Box` or `&` to create a trait object that supports dynamic dispatch for `async` traits. Define your trait with `async` methods, then store implementations in a collection using `Box<dyn TraitName>` to call methods polymorphically at runtime.

How to Use Async Traits with Dynamic Dispatch

Use the dyn keyword with a pointer type like Box or & to create a trait object that supports dynamic dispatch for async traits. Define your trait with async methods, then store implementations in a collection using Box<dyn TraitName> to call methods polymorphically at runtime.

use std::future::Future;

trait AsyncDraw {
    fn draw(&self) -> Box<dyn Future<Output = ()> + Send>;
}

struct Button;
struct Image;

impl AsyncDraw for Button {
    fn draw(&self) -> Box<dyn Future<Output = ()> + Send> {
        Box::new(async { /* ... */ })
    }
}

impl AsyncDraw for Image {
    fn draw(&self) -> Box<dyn Future<Output = ()> + Send> {
        Box::new(async { /* ... */ })
    }
}

fn run_screen(components: Vec<Box<dyn AsyncDraw>>) {
    for component in components {
        // component.draw().await; // Requires async context
    }
}