blockchain - 如何在solidity 0.5.2版中调用另一个合约内的合约？

Question

我正在使用solidity 0.5.2版

pragma solidity ^0.5.2;

contract CampaignFactory{
address[] public deployedCampaigns;

function createCampaign(uint minimum) public{
    address newCampaign  = new Campaign(minimum,msg.sender);  //Error 
//here!!!
    deployedCampaigns.push(newCampaign);
} 

function getDeployedCampaigns() public view returns(address[] memory){
    return deployedCampaigns;
}
}

我在分配调用 CampaignFactory 合同中的 Campaign 合同时遇到错误

TypeError: Type contract Campaign is not implicitly convertible to expected 
type address.        
address newCampaign  = new Campaign(minimum,msg.sender);

我有另一个名为 Campaign 的合同，我想在 CampaignFactory 中访问它。

contract Campaign{
//some variable declarations and some codes here......

我有如下构造函数

constructor (uint minimum,address creator) public{
    manager=creator;
    minimumContribution=minimum;

}

Answer 1

你可以投它：

address newCampaign = address(new Campaign(minimum,msg.sender));

或者更好的是，停止使用address并使用更具体的类型Campaign：

pragma solidity ^0.5.2;

contract CampaignFactory{
    Campaign[] public deployedCampaigns;

    function createCampaign(uint minimum) public {
        Campaign newCampaign = new Campaign(minimum, msg.sender);
        deployedCampaigns.push(newCampaign);
    } 

    function getDeployedCampaigns() public view returns(Campaign[] memory) {
        return deployedCampaigns;
    }
}

Answer 2

要从另一个合约调用现有合约，请在 cast 中传递合约地址

pragma solidity ^0.5.1;

contract D {
    uint x;
    constructor (uint a) public  {
        x = a;
    }
    function getX() public view returns(uint a)
    {
        return x;
    }
}

contract C {
//DAddress : is the exsiting contract instance address after deployment
    function getValue(address DAddress) public view returns(uint a){
        D d =D(DAddress);
        a=d.getX();
    }
}