メインコンテンツまでスキップ
Version: 0.18.0

Children

General usage#

Most of the time, when allowing a component to have children, you don't care what type of children the component has. In such cases, the below example will suffice.

use yew::{html, Children, Component, Html, Properties};
#[derive(Properties, Clone)]pub struct ListProps {    #[prop_or_default]    pub children: Children,}
pub struct List {    props: ListProps,}
impl Component for List {    type Properties = ListProps;    // ...
    fn view(&self) -> Html {        html! {            <div class="list">                { for self.props.children.iter() }            </div>        }    }}

Advanced usage#

Typed children#

In cases where you want one type of component to be passed as children to your component, you can use yew::html::ChildrenWithProps<T>.

use yew::{html, ChildrenWithProps, Component, Html, Properties};
// ...
#[derive(Properties, Clone)]pub struct ListProps {    #[prop_or_default]    pub children: ChildrenWithProps<Item>,}
pub struct List {    props: ListProps,}
impl Component for List {    type Properties = ListProps;    // ...
    fn view(&self) -> Html {        html! {            <div class="list">                { for self.props.children.iter() }            </div>        }    }}

Enum typed children#

Of course, sometimes you might need to restrict the children to a few different components. In these cases, you have to get a little more hands-on with Yew.

The derive_more crate is used here for better ergonomics. If you don't want to use it, you can manually implement From for each variant.

use yew::{    html, html::ChildrenRenderer, virtual_dom::VChild,     Component, Html, Properties};
// `derive_more::From` implements `From<VChild<Primary>>` and// `From<VChild<Secondary>>` for `Item` automatically!#[derive(Clone, derive_more::From)]pub enum Item {    Primary(VChild<Primary>),    Secondary(VChild<Secondary>),}
// Now, we implement `Into<Html>` so that yew knows how to render `Item`.impl Into<Html> for Item {    fn into(self) -> Html {        match self {            Self::Primary(child) => child.into(),            Self::Secondary(child) => child.into(),        }    }}
#[derive(Properties, Clone)]pub struct ListProps {    #[prop_or_default]    pub children: ChildrenRenderer<Item>,}
pub struct List {    props: ListProps,}
impl Component for List {    type Properties = ListProps;    // ...
    fn view(&self) -> Html {        html! {            <div class="list">                { for self.props.children.iter() }            </div>        }    }}

Optional typed child#

You can also have a single optional child component of a specific type too:

use yew::{html, virtual_dom::VChild, Component, Html, Properties};
#[derive(Clone, Properties)]pub struct PageProps {    #[prop_or_default]    pub sidebar: Option<VChild<PageSideBar>>,}
struct Page {    props: PageProps,}
impl Component for Page {    type Properties = PageProps;    // ...
    fn view(&self) -> Html {        html! {            <div class="page">                { self.props.sidebar.clone().map(Html::from).unwrap_or_default() }                // ... page content            </div>        }    }}
// The page component can be called either with the sidebar or without: 
// Page without sidebarhtml! {    <Page />}
// Page with sidebarhtml! {<Page sidebar=html_nested! {    <PageSideBar />    } />}