Cannot read property 'methods' of undefined

[ZhBoKn]

i want to use the "set" function ,but the console tells me that i can 't ,and i want to know how can i use the abi ....... here are my code !

`import React, { Component } from "react"; import SimpleStorageContract from "./contracts/SimpleStorage.json"; import getWeb3 from "./getWeb3"; import "./App.css";

var instance;

class App extends Component { state = { storageValue: 0, web3: null, accounts: null, contract: null };

componentDidMount = async () => { try { const web3 = await getWeb3(); // Use web3 to get the user's accounts. const accounts = await web3.eth.getAccounts(); // Get the contract instance. const networkId = await web3.eth.net.getId(); // Get network provider and web3 instance. const deployedNetwork = SimpleStorageContract.networks[networkId];

  instance = new web3.eth.Contract(SimpleStorageContract.abi
    ,deployedNetwork && deployedNetwork.address,);

  // Set web3, accounts, and contract to the state, and then proceed with an
  // example of interacting with the contract's methods.
  this.setState({ web3, accounts, contract: instance }, this.runExample);
} catch (error) {
  // Catch any errors for any of the above operations.
  alert(
    `Failed to load web3, accounts, or contract. Check console for details.`,
  );
  console.error(error);
}

}; runExample = async () => { const { accounts, contract } = this.state;

// Stores a given value, 5 by default.
await contract.methods.set(1000).send({ from: accounts[0] });

// Get the value from the contract to prove it worked.
const response = await contract.methods.get().call();

// Update state with the result.
this.setState({ storageValue: response });

};

render() { if (!this.state.web3) { return

Loading Web3, accounts, and contract...

; } return (

Good to Go!

Your Truffle Box is installed and ready.

Smart Contract Example

If your contracts compiled and migrated successfully, below will show a stored value of 1000 (by default).

Try changing the value stored on line 40 of App.js.

The stored value is: {this.state.storageValue}

{ var value=this.refs.Change_data_Input.value; console.log(instance); console.log("111111111111"); instance.contract.methods.set(value).send({from:this.state.web3.eth.getCoinbase()}).then((result)=>{ console.log("helloworld"); }) // instance.set(value).send({from:this.state.web3.eth.getCoinbase()}).then((result)=>{ // console.log("helloworld"); // }) }} >修改

);

} }

export default App; `