小编mik*_*gio的帖子

我useState用来管理状态，它工作正常。但是当我在它的内部返回状态时，它总是初始值

import react, {useState} from 'react'

const MyComponent = () => {
    const [myState, setMyState] = useState({
        value: 'initial value',
        setValue: (newValue) => {
            setMyState({...myState, value: newValue})
            console.log(myState.value) //<--always is 'initial value'
        }
    })

    return(
        <>
            <p>{myState.value}</p> //<-- it's working fine
            <input value={myState.value} onChange={(e) => myState.setValue(e.target.value)} /> //<--working fine too

        </>
    )
}

我期望console.log输入的值，但实际输出总是初始值

我正在尝试发布FormData包括 aFile和 a Collection。

这是我的模型：

public class Content
{
    public string Name { get; set; }
    public string Link { get; set; }
}
public class Model
{
    public IEnumerable<Content> Contents { get; set; }
    public IFormFile File { get; set; }
}

这是我的操作：

[HttpPost]
public async Task InsertAsync([FromForm]Model dataPost)
{
    await _services.Create(dataPost);
}

我FormData在 JavaScript 中是：

const formData = new FormData();
formData.append("File", myFile, "image.jpg")
formData.append("Contents", arrayOfContent)

这是header：

'Content-Type': `multipart/form-data`

“文件”工作正常，但“内容”始终为空。 …

我有一个像这样的简单动作：

[HttpGet]
public async Task<string> GetHtml()
{
    Console.WriteLine("Run=======================================================");
    await Task.Delay(5000);
    Console.WriteLine("End=======================================================");
    return "ok";
}

我快速打开三个窗口，然后转到该 URL。我预计结果如下：

Run=======================================================
Run=======================================================
Run=======================================================
End=======================================================
End=======================================================
End=======================================================

但是，事实并非如此！相反，结果是：

Run=======================================================
End=======================================================
Run=======================================================
End=======================================================
Run=======================================================
End=======================================================

此外，当第一次运行完成后，第二次请求开始。为什么？

My problems are so hard to explain.

So, look at my code below.

I have a class model as follows:

public class MyModel{
    public int ID{get;set;}
    public List<string> CHILD{get;set;}
}

I have a list of MyModel, and some of elements have same ID.

How can I create a new list from list of MyModel with unique ID and CHILD has combined?

Thank you so much