Reactjs {payment.fname} )) } 您实际上是在设置状态,这会导致重新启动,设置状态,重新启动,等等。这在功能上是不等价的,它在以后每次打开菜单时都显示--选择一个状态--,而最初的实现只在最初显示它。@AvinKavish,我不明白您的意思。在Ry
{payment.fname} )) }Reactjs {payment.fname} )) } 您实际上是在设置状态,这会导致重新启动,设置状态,重新启动,等等。这在功能上是不等价的,它在以后每次打开菜单时都显示--选择一个状态--,而最初的实现只在最初显示它。@AvinKavish,我不明白您的意思。在Ry,reactjs,react-hooks,Reactjs,React Hooks,{payment.fname} )) } 您实际上是在设置状态,这会导致重新启动,设置状态,重新启动,等等。这在功能上是不等价的,它在以后每次打开菜单时都显示--选择一个状态--,而最初的实现只在最初显示它。@AvinKavish,我不明白您的意思。在Ryan的演示中,“---选择一个状态---”根本不显示,可以省略。你能解释一下你的意思吗?哦,是的,我只是假设,因为它被称为初始值,它的行为应该是这样的。我的回答显示了一个实现,其中“选择状态”最初显示,但消失,无法重新拾取。@AvinKavis
您实际上是在设置状态,这会导致重新启动,设置状态,重新启动,等等。这在功能上是不等价的,它在以后每次打开菜单时都显示
--选择一个状态--
,而最初的实现只在最初显示它。@AvinKavish,我不明白您的意思。在Ryan的演示中,“---选择一个状态---”根本不显示,可以省略。你能解释一下你的意思吗?哦,是的,我只是假设,因为它被称为初始值,它的行为应该是这样的。我的回答显示了一个实现,其中“选择状态”最初显示,但消失,无法重新拾取。@AvinKavish,酷。顺便说一句,我的新工作似乎已经通知你了。怎么会这样?我也想使用这个解决方案。
import React, { useState } from "react";
import ReactDOM from "react-dom";
const StateSelector = () => {
const initialValue = [
{ id: 0,value: " --- Select a State ---" }];
const allowedState = [
{ id: 1, value: "Alabama" },
{ id: 2, value: "Georgia" },
{ id: 3, value: "Tennessee" }
];
const [stateOptions, setStateValues] = useState(initialValue);
// initialValue.push(...allowedState);
console.log(initialValue.length);
setStateValues(allowedState); // Not sure why cannot I reset the state in here for an array.
return (<div>
<label>Select a State:</label>
<select>
{stateOptions.map((localState, index) => (
<option key={localState.id}>{localState.value}</option>
))}
</select>
</div> ); };
const rootElement = document.getElementById("root");
ReactDOM.render(<StateSelector />, rootElement);
import React, { useState, useEffect } from "react";
import ReactDOM from "react-dom";
const StateSelector = () => {
const initialValue = [
{ id: 0, value: " --- Select a State ---" }];
const allowedState = [
{ id: 1, value: "Alabama" },
{ id: 2, value: "Georgia" },
{ id: 3, value: "Tennessee" }
];
const [stateOptions, setStateValues] = useState(initialValue);
// initialValue.push(...allowedState);
console.log(initialValue.length);
// ****** BEGINNING OF CHANGE ******
useEffect(() => {
// Should not ever set state during rendering, so do this in useEffect instead.
setStateValues(allowedState);
}, []);
// ****** END OF CHANGE ******
return (<div>
<label>Select a State:</label>
<select>
{stateOptions.map((localState, index) => (
<option key={localState.id}>{localState.value}</option>
))}
</select>
</div>);
};
const rootElement = document.getElementById("root");
ReactDOM.render(<StateSelector />, rootElement);
const StateSelector = () =>{
const [selectedStateOption, setselectedStateOption] = useState(0);
return (
<div>
<label>Select a State:</label>
<select>
{ALL_STATE_VALS.map((option, index) => (
<option key={option.id} selected={index===selectedStateOption}>{option.value}</option>
))}
</select>
</div>);
)
}
import React, { useState } from "react";
import ReactDOM from "react-dom";
const initialValue = { id: 0,value: " --- Select a State ---" };
const options = [
{ id: 1, value: "Alabama" },
{ id: 2, value: "Georgia" },
{ id: 3, value: "Tennessee" }
];
const StateSelector = () => {
const [ selected, setSelected ] = useState(initialValue);
return (
<div>
<label>Select a State:</label>
<select value={selected}>
{selected === initialValue &&
<option disabled value={initialValue}>{initialValue.value}</option>}
{options.map((localState, index) => (
<option key={localState.id} value={localState}>
{localState.value}
</option>
))}
</select>
</div>
);
};
const rootElement = document.getElementById("root");
ReactDOM.render(<StateSelector />, rootElement);
setStateValues(allowedState);
setTimeout(
() => setStateValues(allowedState),
1000
)
let paymentList = [
{"id":249,"txnid":"2","fname":"Rigoberto"}, {"id":249,"txnid":"33","fname":"manuel"},]
<div className="card-body">
<div className="table-responsive">
<table className="table table-striped">
<thead>
<tr>
<th>Transaction ID</th>
<th>Name</th>
</tr>
</thead>
<tbody>
{
paymentList.map((payment, key) => (
<tr key={key}>
<td>{payment.txnid}</td>
<td>{payment.fname}</td>
</tr>
))
}
</tbody>
</table>
</div>
</div>