在Windows Phone 8中獲取包含多個電話號碼的聯系人列表

Question

在我的Windows手機應用程序中，我想獲得Windows Phone 8的聯系人列表，每個聯系人都有兩個或更多的電話號碼，我想在我的應用程序中顯示聯系人姓名和電話號碼，我在下面嘗試：

xaml page:
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <StackPanel>
                <TextBlock Name="ContactResultsLabel" Text="results are loading..." Style="{StaticResource PhoneTextLargeStyle}" TextWrapping="Wrap" />

                <ListBox Name="ContactResultsData" ItemsSource="{Binding listOfContacts}" Height="200" Margin="24,0,0,0" >
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <TextBlock Name="ContactResultsName" Text="{Binding Path=Name}" />

                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>
            </StackPanel>
            <Button x:Name="ButtonContacts"
                    Content="Get All Contacts"
                    FontSize="15"
                    Width="200"
                    Height="70"
                    Background="AliceBlue"
                    Foreground="Blue"
                    HorizontalAlignment="Left"
                    Click="ButtonContacts_Click"></Button>
            <Button x:Name="MergeContacts"
                    Content="Merge Contacts"
                    FontSize="15"
                    Width="200"
                    Height="70"
                    Background="AliceBlue"
                    Foreground="Blue"
                    HorizontalAlignment="Right"
                    Click="MergeContacts_Click"></Button>
        </Grid>

以下是xaml.cs頁面：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using GetContacts.Resources;
using Microsoft.Phone.UserData;

namespace GetContacts
{
    public partial class MainPage : PhoneApplicationPage
    {
        // Constructor
        public MainPage()
        {
            InitializeComponent();
        }
        private void ButtonContacts_Click(object sender, RoutedEventArgs e)
        {
            Contacts cons = new Contacts();
            cons.SearchCompleted += new EventHandler<ContactsSearchEventArgs>(Contacts_SearchCompleted);

            cons.SearchAsync(String.Empty, FilterKind.None, "Contacts Test #1");
        }

        void Contacts_SearchCompleted(object sender, ContactsSearchEventArgs e)
        {
            try
            {
                List<CustomContact> listOfContact = new List<CustomContact>();
                foreach (var c in e.Results)
                {
                    CustomContact contact = new CustomContact();
                    contact.Name = c.DisplayName;
                    int count = c.PhoneNumbers.Count();
                    for (int i = 0; i < count; i++)
                    {
                        if (count > 0)
                        {
                            contact.Number[i] = c.PhoneNumbers.ElementAt(i).PhoneNumber.ToString();
                        }
                        else
                        {
                            contact.Number[i] = "";
                        }

                    }
                    listOfContact.Add(contact);
                }

                ContactResultsData.ItemsSource = listOfContact;
            }
            catch (System.Exception)
            {
                //No results
            }
            if (ContactResultsData.Items.Any())
            {
                ContactResultsLabel.Text = "results";
            }
            else
            {
                ContactResultsLabel.Text = "no results";
            }
        }
    }
}

但是當我進入CustomContact contact = new CustomContact();類時， CustomContact contact = new CustomContact(); 它讓我進入默認的構造函數即空。 以下是我的CustomContact類

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using GetContacts.Resources;
using Microsoft.Phone.UserData;

namespace GetContacts
{
    class CustomContact
    {
        public string Name { get; set; }
        public string[] Number
        {
            get;
            set;
        }
       // public string Number1 { get; set; }

        public CustomContact()
        {
        }

        //CTOR that takes in a Contact object and extract the two fields we need (can add more fields)
        public CustomContact( Contact contact)
        {
            Name = contact.DisplayName;
            int count = contact.PhoneNumbers.Count();
            for (int i = 0; i < count; i++)
            {
                if (count > 0 && contact.PhoneNumbers.ElementAt(i).PhoneNumber != null && !string.IsNullOrEmpty(contact.PhoneNumbers.ElementAt(i).PhoneNumber))
                {
                    Number[i] = contact.PhoneNumbers.ElementAt(i).PhoneNumber.ToString();
                }
                else
                {
                   Number[i] = "";
                }
            }
        }
    }
}

但它沒有正常工作，並沒有顯示多個PhoneNumber的聯系人列表，我在這行contact.Number[i] = c.PhoneNumbers.ElementAt(i).PhoneNumber.ToString(); 異常是Object reference not set to an instance of an object.為Object reference not set to an instance of an object. 。 我不明白我哪里弄錯了。 請建議我，等待回復。 謝謝。

Answer 1

你必須再檢查一個條件。

if(count>0 && c.PhoneNumbers.ElementAt(i)!=null && !string.IsNullOrEmpty(c.PhoneNumbers.ElementAt(i).PhoneNumber))
{
contact.Number[i] = c.PhoneNumbers.ElementAt(i).PhoneNumber.ToString();
}

Answer 2

和達維爾說的一樣，也檢查一下

c.PhoneNumbers.ElementAt(i).PhoneNumber== null ?

可能有一些用戶沒有電話號碼

Answer 3

我希望這對你有幫助。 在CustomContact模型中，Numbers變量應該是多個聯系人號碼的字符串列表，因此CustomContact模型應該是：

 class CustomContact
{
    public string Name { get; set; }

    public List<string> Numbers { get; set; }


    public CustomContact()
    {
    }

    public CustomContact(string displayName, List<string> phoneNumbers)
    {
        this.Name = displayName;
        this.Numbers = phoneNumbers;
    }
}

並在GetContacts后面的代碼頁中將數字定義為字符串列表：

 public partial class GetContacts : PhoneApplicationPage
{
    List<string> numbers = new List<string>();
    public GetContacts()
    {
        InitializeComponent();
    }

。 。 。 和Contacts_SearchCompleted如下：

 void Contacts_SearchCompleted(object sender, ContactsSearchEventArgs e)
    {

            List<CustomContact> listOfContact = new List<CustomContact>();
            foreach (var c in e.Results)
            {

                CustomContact contact = new CustomContact();
                contact.Name = c.DisplayName;
                 numbers.Clear();
                int count = c.PhoneNumbers.Count();
                for (int i = 0; i < count; i++)
                {

                    if (count > 0)
                    {

                    numbers.Add (c.PhoneNumbers.ElementAt(i).PhoneNumber.ToString());
                    }
                    contact.Numbers = numbers;

                }
                listOfContact.Add(contact);

            }

            ContactResultsData.ItemsSource = listOfContact;

        if (ContactResultsData.Items.Any())
        {
            ContactResultsLabel.Text = "results";
        }
        else
        {
            ContactResultsLabel.Text = "no results";
        }
    }

並在UI中顯示名稱和數字使用此代碼

  <ListBox Name="ContactResultsData" ItemsSource="{Binding listOfContacts}" Height="200">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <TextBlock Name="ContactResultsName" Text="{Binding Path=Name}" />
                        <ListBox Name="ContactResultsNumbers" ItemsSource="{Binding Numbers}" Foreground="White" Height="50" Margin="24,0,0,0" />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>