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背景

我正在关注本教程：https ://www.toptal.com/ios/sync-data-across-devices-with-cloudkit

他有一个部分来处理用 swift 编写的来自 CloudKit 的部分错误：

public func isSpecificErrorCode(code: CKError.Code) -> Bool {
    var match = false
    if self.code == code {
        match = true
    }
    else if self.code == .partialFailure {
        // This is a multiple-issue error. Check the underlying array
        // of errors to see if it contains a match for the error in question.
        guard let errors = partialErrorsByItemID else {
            return false
        }
        for (_, error) in errors {
            if let cke = error as? CKError {
                if cke.code == code {
                    match = true
                    break
                }
            }
        }
    }
    return match
}

我正在尝试将其转换为 Xamarin 的 C#。但是我正在努力如何处理 CloudKit 错误，因为 Xamarin 似乎缺少 CKError 类。我在静态类中编写了以下内容：

    static public bool isSpecificErrorCode(CKErrorCode code, NSError error) {
        var match = false;
        if ((int)code == error.Code) {
            match = true;
        }
        else if (code == CKErrorCode.PartialFailure) {
            // This is a multiple-issue error. Check the underlying array
            // of errors to see if it contains a match for the error in question.
            NSDictionary errors = (NSDictionary)error.UserInfo.ObjectForKey(CKErrorFields.PartialErrorsByItemIdKey);
            foreach (KeyValuePair<NSObject, NSObject> item in errors) {
                var err = (NSError) item.Value;
                if (err.Code == (int)code) {
                    match = true;
                    break;
                }
            }
        }

        return match;
    }

主要问题

我的上述解决方案似乎笨拙，老实说不确定它是否有效。由于下面的编译错误，我无法真正测试。

但真正的问题来了。在他的下一个方法中，他以某种方式访问clientRecord​​ and serverRecord，我认为这是 a 的字段CKError？我什至如何访问这些？我在我不理解的行中插入了一个箭头。当我只能访问 Xamarin 中的 NSError 时，似乎我需要访问 CKError 的一些内部属性。

// ServerRecordChanged errors contain the CKRecord information
// for the change that failed, allowing the client to decide
// upon the best course of action in performing a merge.
public func getMergeRecords() -> (CKRecord?, CKRecord?) {
    if code == .serverRecordChanged {
        // This is the direct case of a simple serverRecordChanged Error.


        //here
        return (clientRecord, serverRecord) // <-- this is what's confusing me!!!
        //here

    }
    guard code == .partialFailure else {
        return (nil, nil)
    }
    guard let errors = partialErrorsByItemID else {
        return (nil, nil)
    }
    for (_, error) in errors {
        if let cke = error as? CKError {
            if cke.code == .serverRecordChanged {
    // This is the case of a serverRecordChanged Error 
    // contained within a multi-error PartialFailure Error.
                return cke.getMergeRecords()
            }
        }
    }
    return (nil, nil)
}

尝试的解决方案（编译错误，从丢失的数据）

这是我微弱的尝试：

    public class MergeRecordPair {
        public CKRecord clientRecord = null;
        public CKRecord serverRecord = null;
    }

    static public MergeRecordPair getMergeRecords(this NSError error) {
        if (error.Code == (int)CKErrorCode.ServerRecordChanged) {
            // This is the direct case of a simple serverRecordChanged Error.
            
            // here
            return new MergeRecordPair {
                clientRecord = clientRecord, // <-- How do I get these?
                serverRecord = serverRecord // <-- How do I get these?
            };
            // here

        }
        if (error.Code == (int)CKErrorCode.PartialFailure) {
            return new MergeRecordPair();
        }
        
        NSDictionary errors = (NSDictionary)error.UserInfo.ObjectForKey(CKErrorFields.PartialErrorsByItemIdKey);
        if (errors == null) {
            return new MergeRecordPair();
        }
    
        foreach (KeyValuePair<NSObject, NSObject> item in errors) {
            var err = (NSError) item.Value;
            if (err.Code == (int)CKErrorCode.ServerRecordChanged) {
                return err.getMergeRecords();
            }
        }
        return new MergeRecordPair();
    }

我确信我尝试的解决方案是否走上了正确的轨道。我不知道clientRecordandserverRecord来自哪里！也许我错过了一些我错过的 Swift 的细微差别。我从来没有快速编码过。任何的意见都将会有帮助。

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