无法将类型'String？.Type'的值转换为预期的参数类型'String？'

Question

我在声明var updater的标题中遇到了错误。

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let destination = segue.destination as? ProductViewController,
            let index = tableViewProducts.indexPathForSelectedRow?.row {

            // Check whether postData array count is greater than index
            let updaterId = postData.count > index ? postData[index] : ""

            // Initialize "productsList" instance and assign the id value and sent this object to next view controller
            var updater = productsList(id: String?, p_name: String?, image: String?, audio: String?)
            updater.id = updaterId
            destination.updater = updater

这是我的产品清单VC：

进口基金会

class productsList {

    let id: String?
    let p_name: String?
    let image: String?
    let audio: String?

    init(id: String?, p_name: String?, image: String?, audio: String?) {
        self.id = id
        self.p_name = p_name
        self.image = image
        self.audio = audio
    }

}

Answer 1

您必须将字符串值（或nil ）作为参数而不是类型String?传递String? ，这就是错误的意思。

更换

var updater = productsList(id: String?, p_name: String?, image: String?, audio: String?)
updater.id = updaterId

与

let updater = productsList(id: updaterId, p_name: nil, image: nil, audio: nil)

并请遵循类名以大写字母开头的命名约定。

Answer 2

这行引起了问题

var updater = productsList(id: String?, p_name: String?, image: String?, audio: String?)

当您初始化对象（即“ ProductList”）时，必须传递文件名“ id”，“ p_name”，“ image”和“ audio”的实际值。

现在，您正在发送“字符串？” ，这是参数的类型，您的函数需要该参数的值。

所以改变它像

var updater = productsList(id: ID_OF_PRODUCT, p_name: NAMEOFPRODUCT, image: URLTOIMAGE/IMAGE, audio: AUDIOURL)

Answer 3

用这个

var updater = productsList(id: updaterId, p_name: nil, image: nil, audio: nil)

代替

var updater = productsList(id: String?, p_name: String?, image: String?, audio: String?)