是否可以通过命名而不是 %@
例如,我有一个直接传递
参数me
和you
。
public static func ConversationByUserId( userId : String ) -> [Message] {
// Either Created By me and sent to you.
// Or, created by you and sent to me
let me = UserRepo.GetLoggedInUser()?.id
var format = "( createdBy == '" + me! + "' && createdTo == '" + userId + "') "
format += " || ( createdBy == '" + userId + "' && createdTo == '" + me! + "') "
print(format)
//prints: ( createdBy == '1' && createdTo == '5') || ( createdBy == '5' && createdTo == '1')
let predicate = NSPredicate(format: format)
return Filter(predicate);
}
注意:Filter(predicate)
执行操作并返回结果。到目前为止,一切都很好。我得到了预期的结果。但我猜这可能会产生像 SQL 攻击这样的问题。
我可以做如下的事情吗:如果可以,怎么做?
var format = "( createdBy == @me && createdTo == @you ) "
format += " || ( createdBy == @you && createdTo == @me ) "
let predicate = NSPredicate(format: format, [ "me" : me, "you" : you ])
到目前为止我取得的成绩是:
format = "( createdBy == %@ && createdTo == %@ ) "
format += " || ( createdBy == %@ && createdTo == %@ ) "
let predicate = NSPredicate(format: format, me!, you, me!, you)
最佳答案
您可以使用 NSPredicate 的 predicateWithSubstitutionVariables
(参见 Apple Docs)。像往常一样创建谓词,使用“$variable”代替您要替换的值:
var format = "( createdBy == $me && createdTo == $you ) "
format += " || ( createdBy == $you && createdTo == $me ) "
let predicate = NSPredicate(format: format)
然后用变量名和你想传递的值创建一个字典:
let subVars = ["me" : me!, "you" : you!]
最后用您的值替换变量名创建谓词:
let finalPredicate = predicate.predicateWithSubstitutionVariables(subVars)
关于ios - NSPredicate 按名称传递 "multiple"参数 [在 Swift 中],我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38136341/