如何從 JavaScript 前端設置 Solidity 合約狀態變數的值？

我正在嘗試從前端 javascript 程式碼為以下契約公共狀態變數設置值。但它似乎不起作用。

合約公共狀態變數：

// Current state of the auction.
address public highestBidder;
uint public highestBid;

在下面的 Javascript 程式碼中，我從 UI 中獲取地址和金額的值並分配給最高出價和最高出價。但它似乎不起作用。我該怎麼做呢？

// Submit bid details, triggered by the "Bid" button
SimpleAuction.prototype.startAuction = function() {
   console.log("inside startAuction");
   var that = this;
   console.log("inside startAuction");
   // Gets form input values
   var address = $("#enter-address").val();
   var amount = $("#enter-amount").val();
   console.log(amount);

   // Validates address using utility function
   if (!isValidAddress(address)) {
       console.log("Invalid address");
       return;
   }
   that.highestBidder = address;
   
    
   // Validate amount using utility function
   if (!isValidAmount(amount)) {
       console.log("Invalid amount");
       return;
   }
   that.highestBid = amount;

這段程式碼解決了這個問題。在 JS 的 bid() 函式中將地址和金額作為交易對像傳遞

// Submit bid details, triggered by the "Bid" button
SimpleAuction.prototype.startAuction = function() {
   console.log("inside startAuction");
   var that = this;
   console.log("inside startAuction");
   // Gets form input values
   var address = $("#enter-address").val();
   var amount = $("#enter-amount").val();
   console.log(amount);

   // Validates address using utility function
   if (!isValidAddress(address)) {
       console.log("Invalid address");
       return;
   }
    
   // Validate amount using utility function
   if (!isValidAmount(amount)) {
       console.log("Invalid amount");
       return;
   }
   
   
   // Calls the public `bid` function from the smart contract
   this.instance.bid(
        {  
           from: address,
           value: amount,
           gas: 100000,
           gasPrice: 100000,
           gasLimit: 100000
       },
      
       function(error, txHash) {
           if (error) {
               console.log(error);
           }
           // If success, wait for confirmation of transaction,
           // then clear form values
           else {
               that.waitForReceipt(txHash, function(receipt) {
                   if (receipt.status) {
                       $("#enter-address").val("");
                       $("#enter-amount").val("");
                   } else {
                       console.log("error");
                   }
               });
           }
       }
   );
};

您正在嘗試更新契約的狀態，在這種情況下，您必須簽署交易。看看這裡sendTransaction的 web3方法。當您查看該方法時，您會注意到參數包含字元串，它是您的智能合約方法的函式 ABI。您可以使用 encodeABI 獲取函式abi。transactionObject``data

然後在您的智能合約中，僅通過以下方式創建變數address public highestBidder;並不意味著可以更新此狀態變數。您必須創建一個 setter 方法或將 setter 方法邏輯包含到另一個方法中，例如：

function setHighestBidder(address _highestBidder) {
   highestBidder = _highestBidder;
}

引用自：https://ethereum.stackexchange.com/questions/85120