Xcode 8, Swift 3:

let gAppVersion = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") ?? "0"
let gAppBuild = Bundle.main.object(forInfoDictionaryKey: "CFBundleVersion") ?? "0"

if let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String {
        lblVersion.text = "Version \(version)"

    }

public var appVersionNumberString: String {
    get {
        return Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as! String
    }
}

看过文档后，我认为以下内容更清晰:

let version = 
NSBundle.mainBundle().objectForInfoDictionaryKey("CFBundleShortVersionString") 
as? String

来源: 使用此方法优于其他访问方法，因为它在键可用时返回键的本地化值。

if let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String {
            self.lblAppVersionValue.text = version
        }

针对Swift 4.0

let version = Bundle.main.infoDictionary!["CFBundleShortVersionString"]!
let build = Bundle.main.infoDictionary!["CFBundleVersion"]!