Refs
ref
关键词可被用在任何 HTML 元素或组件内部以获得该项所附加到的 DOM 元素。这可被用于在 view
生命周期方法之外来对 DOM 进行更改。
这对于获取 canvas 元素或者滚动到页面的不同部分是有用的。
For example, using a NodeRef
in a component's rendered
method allows you to make draw calls to
a canvas element after it has been rendered from view
.
语法如下:
use web_sys::Element;
use yew::{html, Component, Context, Html, NodeRef};
struct Comp {
node_ref: NodeRef,
}
impl Component for Comp {
type Message = ();
type Properties = ();
fn create(_ctx: &Context<Self>) -> Self {
Self {
node_ref: NodeRef::default(),
}
}
fn view(&self, _ctx: &Context<Self>) -> Html {
html! {
<div ref={self.node_ref.clone()}></div>
}
}
fn rendered(&mut self, _ctx: &Context<Self>, _first_render: bool) {
let has_attributes = self.node_ref
.cast::<Element>()
.unwrap()
.has_attributes();
}
}