javascript - 类型错误 : undefined is not an object ('_this.props' )

Question

我无法解决这个问题。你能帮助我吗。评估“this.props.speciesSelection.modalize”

<BarcodeInput
        speciesSelection={this.props.speciesSelection}
        species={species[0]}
        barcode={{ manufacturerValue: "", codeValue: "" }}
        onChangeText={this.onChangeText}
      />


 class BarcodeInput extends React.Component<Props, State> {
  onPrefixPress = () => {
    Keyboard.dismiss();
    this.props.speciesSelection.modalize.open();
    this.props.speciesSelection.modalizeOpened = true;
 }

当我触摸按钮 onPrefixPress 时出现红色框

Answer 1

看起来您正在尝试调用一个未定义的函数(通过 props 传递)。使 speciesSelection 属性可选。

interface Props {
  species: Species;
  barcode: BarcodeState;
  speciesSelection?: any;
  onChangeText: (prop: keyof BarcodeState, value: string) => void;
}

interface State { }

class BarcodeInput extends React.Component<Props, State> {
  onPrefixPress = () => {
    Keyboard.dismiss();
    this.props.speciesSelection && this.props.speciesSelection.modalize.open();
    this.props.speciesSelection && this.props.speciesSelection.modalizeOpened = true;
  }

或者检查它为什么未定义。