javascript - react js 多图像上传与预览

Question

使用 React js 我需要多张图片上传预览 我尝试使用以下代码无法正常工作，它在控制台中显示错误

Uncaught DOMException: Failed to set the 'value' property on 'HTMLInputElement': This input element accepts a filename, which may only be programmatically set to the empty string.

uploadImage(e){
    var numFiles = e.target.files.length; 
    for (var i = 0, numFiles = e.target.files.length; i < numFiles; i++){ 
            var file = e.target.files[i];
            if(!file.type.match('image'))
            continue;
            var reader = new FileReader();
        reader.onload = function(e) {
            setOfImages.push({
              fileName:file.name,
              image:e.target.result.split(',')[1]
            });
            for(var j = 0; j<setOfImages.length; j++) {
                $('.placeholder-blk').prepend('<div class="image-placeholder"><img src="data:image/jpeg;base64,'+ setOfImages[j].image +'" /></div>');
            }
            console.log(setOfImages);
        }
        reader.readAsDataURL(file);
    }
}
<input type="file" name="image-uploder" id="image-uploder" className="file-loader" onChange={this.uploadImage.bind(this)} multiple />

Answer 1

您是否尝试将值添加到状态并从状态填充名称。有点像

<input type="file" name={this.state.setOfImages} id="image-uploder" className="file-loader" onChange={this.uploadImage.bind(this)} multiple />

并在您的函数内部填充状态。

this.setState({setOfImages: JSON.stringify(setOfImages)})

像这样。

export class Demo extends React.Component{
constructor(props){
    super(props)
    this.state = {
        setOfImages : []
    }
}
setOfImages(event){
    event.preventDefault();
    this.setState({
        setOfImages: ["hello", "hi"]
    })
}
render(){
    return (
        <div>
            <input value={this.state.setOfImages}/>
            <button onClick={this.setOfImages.bind(this)}/>
        </div>
    )
}
}

现在首先将用空数组填充输入。当您单击按钮时，状态将通过设置 setOfImages = ["hello", "hi"] 并将输入值设置为这些值而改变。