How to transfer ether to smart contract by msg.value?

Question

I want to transfer some ether form my address to the smart contract, I have tried the code below but it doesn't work. How to transfer ether through msg.sender?

pragma solidity >=0.7.0 <0.9.0;

contract Test {

    function testTransfer() external payable {
        bool sent = payable(address(this)).send(msg.value);
        require(sent, "invalid balance");
    }

}

Once I trigger the function with the value of 1 ether, the error output is as below:

I'm sure that I have enough Ether in my address. What should I do to transfer the Ether? Thanks!

Answer 1

The transaction fails because the smart contract is trying to transfer the ether to himself, and the smart contract doesn't have defined the receive function so it can receive ether that way, for your example you could simply remove all the code inside the function and make another function to check the contract balance and it will work

pragma solidity >=0.7.0 <0.9.0;

contract Test {

     function testTransfer() external payable {}
     function getBalance() external view returns (uint256) {
       return address(this).balance;
     }
}