如何将图像从React上传到ASP.NET Core Web API? [英] How to upload image from React to ASP.NET Core Web API?

问题描述

我在mt服务器端具有Web API控制器

I have Web API controller in mt server side

[HttpPost("CreateImage")]
    public void CreateImage([FromBody] ImageDTO img)
    {
        Image image = new Image { FileName = img.FileName };
        byte[] imageData = null;
        using (var binaryReader = new BinaryReader(img.Image.OpenReadStream()))
        {
            imageData = binaryReader.ReadBytes((int)img.Image.Length);
        }
        image.Picture = imageData;

        imageRepo.Create(image);

    }

ImageDTO在哪里

Where ImageDTO is

     public class ImageDTO
    {
        public string FileName { get; set; }

        public IFormFile Image { get; set; }
    }

和类似Image.cs

and Image.cs like this

public class Image
   {
      public int Id { get; set; }

      public string FileName{ get; set; }

      public byte[] Picture { get; set; }

      public List<User> Users { get; set; }
   }

这就是我用来在React客户端上处理和发送图像的东西:

And this is what I using for handling and sending image on React client:

<form>
        <p>
            <label>Аватар</label>
            <input name="Avatar" id = 'img' type="file" class="form-control" onChange={(e)=>this.handleImageChange(e)}/>
        </p>
        <p>
            <input type="submit" value="Добавить" onClick={this.sendImage}/>
        </p>
</form>
      <div className="imgPreview">
      {$imagePreview}
    </div>

将文件处理为状态的功能

function for handling file into state

    handleImageChange(e) {
    e.preventDefault();
    let form = new FormData();
    for (var index = 0; index < e.target.files; index++) {
      var element = e.target.files[index];
      form.append('file', element);
  }
    this.setState({file: form});
  }

在服务器上发送

async sendImage(event) {
event.preventDefault();

console.log(this.state.file);
await addImage(this.state.file);
console.log('it works');}

addImge函数:

addImge function:

addImage = async ( image)  => {

    await fetch('https://localhost:44331/api/users/CreateImage',
        {
            method: 'POST',
            mode: 'cors',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json',
                'Authorization': 'Bearer ' + sessionStorage.tokenKey
            },
             body:  JSON.stringify({
                FileName: 'Img',
                Image: image
            })
        }
    )
}

但是当它在服务器上发送请求时，它返回错误400，表示错误请求".因此，我认为这可能是发送的数据类型错误或类似的错误.也许有人看到错误或可以解决的问题.或者有人可以展示一个从React向Web Api服务器发送图像的可行示例.我需要你们的帮助！

But when it`s sending request on server it return Error 400, which means "Bad Request". So I think it is may be wrong type of data sent or something like that. Maybe someone sees a mistake or something that can be fixed. Or someone could show a working example of sending images from React to Web Api server. I need your help guys!

推荐答案

要上传，请注意以下几点:

For uploading, you need to pay attention to points below:

1. 您需要将 formdata 与 FromForm
一起使用
2. formdata中的字段应与模型字段相对应.

步骤:

1. 更改控制器动作.

1. Change the Controller action.

public void CreateImage([FromForm] ImageDTO img)
{

}

客户代码:

Client Code:

async sendImage(event) {
    event.preventDefault();
    console.log(this.state.file);
    await this.addImage(this.state.file);
    console.log('it works');
};
addImage = async (image) => {
    await fetch('https://localhost:44385/api/users/CreateImage',
        {
            method: 'POST',
            mode: 'cors',
            headers: {
                'Accept': 'application/json',
                'Authorization': 'Bearer ' + sessionStorage.tokenKey
            },
            body: this.state.file
        }
    )
}

handleImageChange(e) {
    e.preventDefault();
    let form = new FormData();
    for (var index = 0; index < e.target.files.length; index++) {
        var element = e.target.files[index];
        form.append('image', element);
    }
    form.append('fileName', "Img");
    this.setState({ file: form });
};    

这篇关于如何将图像从React上传到ASP.NET Core Web API?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！