IOS联系人Xamarin.Forms中的邮政地址

Question

我正在Xamarin.Forms项目中编写一个C＃应用，该项目显示联系人姓名和街道地址。我无法从CNContact提取地址并将联系人地址分配给字符串。

这很明显，但是我被卡住了！

    public List<Contact> GetContacts()
    {
        contactList = new List<Contact>();

        var store = new Contacts.CNContactStore();

        var ContainerId = new CNContactStore().DefaultContainerIdentifier;
        var predicate = CNContact.GetPredicateForContactsInContainer(ContainerId);

        var fetchKeys = new NSString[] { CNContactKey.Identifier, CNContactKey.GivenName, CNContactKey.FamilyName, CNContactKey.Birthday, CNContactKey.PostalAddresses, CNContactKey.ImageData };

        NSError error;

        var IPhoneContacts = store.GetUnifiedContacts(predicate, fetchKeys, out error);

        foreach(var c in IPhoneContacts)
        {
            var contact = new Contact();

            contact.FirstName = c.GivenName;
            contact.FamilyName = c.FamilyName;

            if(c.PostalAddresses.Length !=0)
            {
                contact.StreetAddress = CNPostalAddressFormatter.GetStringFrom(c.PostalAddresses, CNPostalAddressFormatterStyle.MailingAddress);
            };

            contactList.Add(contact);
        }

        return contactList;
    }

Answer 1

[Fetching Existing Contacts在iOS中：

[[First，您需要在Info.plist中添加关注权限：

<key>NSContactsUsageDescription</key>  
<string>This app requires contacts access to function properly.</string>

[Second，您可以创建一个包含需求联系信息的模型，如下所示：

public class ContactModel
{
    public IList PhoneNumbers { get; set; }
    public string GivenName { get; set; }
    public string FamilyName { get; set; }
}

Third，创建一个函数以获取信息：

public List<ContactModel> ReadContacts()
{
    var response = new List<ContactModel>();
    try
    {
        //We can specify the properties that we need to fetch from contacts  
        var keysToFetch = new[] {
    CNContactKey.PhoneNumbers, CNContactKey.GivenName, CNContactKey.FamilyName
};
        //Get the collections of containers  
        var containerId = new CNContactStore().DefaultContainerIdentifier;
        //Fetch the contacts from containers  
        using (var predicate = CNContact.GetPredicateForContactsInContainer(containerId))
        {
            CNContact[] contactList;
            using (var store = new CNContactStore())
            {
                contactList = store.GetUnifiedContacts(predicate, keysToFetch, out
                    var error);
            }
            //Assign the contact details to our view model objects  
            response.AddRange(from item in contactList
                                where item?.EmailAddresses != null
                                select new ContactModel
                                {
                                    PhoneNumbers = item.PhoneNumbers,
                                    GivenName = item.GivenName,
                                    FamilyName = item.FamilyName
                                });
        }
    }
    catch (Exception e)
    {
        Console.WriteLine(e);
        throw;
    }
    return response;
}

Fourth，调用func：

List<ContactModel> contacts = ReadContacts();
ContactModel contactVm;
for (int i = 0; i < contacts.Count; i++)
{
    contactVm = contacts[i];
    Console.WriteLine("Contact is : " + contactVm.FamilyName);
    Console.WriteLine("Contact is : " + contactVm.GivenName);
    Console.WriteLine("Contact is : " + contactVm.PhoneNumbers);
}

第五，输出打印信息（来自iPhone模拟器），如下所示：

Contact is : Bell
Contact is : Kate
Contact is : Contacts.CNLabeledValue`1[Contacts.CNPhoneNumber][]
Contact is : Higgins
Contact is : Daniel
Contact is : Contacts.CNLabeledValue`1[Contacts.CNPhoneNumber][]
Contact is : Appleseed
Contact is : John
Contact is : Contacts.CNLabeledValue`1[Contacts.CNPhoneNumber][]
Contact is : Haro
Contact is : Anna
Contact is : Contacts.CNLabeledValue`1[Contacts.CNPhoneNumber][]
Contact is : Zakroff
Contact is : Hank
Contact is : Contacts.CNLabeledValue`1[Contacts.CNPhoneNumber][]
Contact is : Taylor
Contact is : David
Contact is : Contacts.CNLabeledValue`1[Contacts.CNPhoneNumber][]

Answer 2

您的问题是CNPostalAddressFormatter.GetStringFrom()方法需要一个CNPostalAddress对象作为参数，但是由于PostalAddresses属性是CNLabeledValue<ValueType>对象的数组，因此您正在传递单个联系人的所有地址。

您应该做的是遍历所有地址，或者默认情况下仅采用第一个地址。确实取决于您要实现的目标。

例如，这将获得第一个CNPostalAddress：

contact.StreetAddress = CNPostalAddressFormatter.GetStringFrom(c.PostalAddresses[0].Value, CNPostalAddressFormatterStyle.MailingAddress);

此外，如果您想知道地址的标签（家庭，工作等），可以这样获得：

c.PostalAddresses[0].Label

然后，实际的CNPostalAddress对象又是这个：

c.PostalAddresses[0].Value