Read Contacts in Xamarin.Forms

Question

I want to read all Names from the AdressBook in the Smartphone. I've tested following code, but it won't work:

CrossContacts.Current.PreferContactAggregation = false;
var hasPermission = CrossContacts.Current.RequestPermission().Result;

if (hasPermission)
{
   Contacts = CrossContacts.Current.Contacts.Select(
      contact => contact.FirstName + " " + contact.LastName);
}

Also Visual Studio throws an exception like following:

System.ArgumentException: Expression of type 'Plugin.Contacts.ProjectionReader 1[System.String]' cannot be used for return type 'System.Linq.EnumerableQuery 1[System.String]'

What's the problem here?

Answer 1

If you want to return all the contacts with the first/last name concatenated together, return them to a List<string> instead of a List<Contact> :

List<string> nameList = CrossContacts.Current.Contacts.Select(contact => contact.FirstName + " " + contact.LastName).ToList();

If you are trying to return the whole Contact record to a List:

List<Contact> contacts = CrossContacts.Current.Contacts.ToList();

Note: Be aware that with unified contacts, a user can have thousands of contacts that could be returned since you are applying no filtering.

Answer 2

我认为这是当前Xamarin插件中的错误： https : //github.com/jamesmontemagno/Xamarin.Plugins/issues/272