無法將類型'String？.Type'的值轉換為預期的參數類型'String？'

Question

我在聲明var updater的標題中遇到了錯誤。

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

這是我的產品清單VC：

進口基金會

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

您必須將字符串值（或nil ）作為參數而不是類型String?傳遞String? ，這就是錯誤的意思。

更換

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

與

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

並請遵循類名以大寫字母開頭的命名約定。

Answer 2

這行引起了問題

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

當您初始化對象（即“ ProductList”）時，必須傳遞文件名“ id”，“ p_name”，“ image”和“ audio”的實際值。

現在，您正在發送“字符串？” ，這是參數的類型，您的函數需要該參數的值。

所以改變它像

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

Answer 3

用這個

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?)