DataGridComboBoxColumn binding trouble

Question

How can I make DataGridComboBoxColumn display the user phone numbers (right now it displays a blank combobox)?

EDIT: Code below has been updated and now works.

<Window x:Class="DataGridTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:DataGridTest"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <DataGrid   
                    x:Name="myDataGrid"
                    Grid.Row="1"
                    AutoGenerateColumns="False"
                    CanUserAddRows="True"
                    ItemsSource="{Binding PersonList}"
            >

            <DataGrid.Columns>
                <DataGridTextColumn  
                                        Header="LastName"                           
                                        Binding="{Binding LastName}"/>
                <DataGridTextColumn 
                                        Header="FirstName"                          
                                        Binding="{Binding FirstName}" />

                  <DataGridComboBoxColumn 
                                    Header="Phone Number"       

                >
                <DataGridComboBoxColumn.ElementStyle>
                    <Style TargetType="{x:Type ComboBox}">
                        <Setter Property="ItemsSource" Value="{Binding PhoneNumbers}" />
                        <Setter Property="SelectedValue" Value="{Binding SelectedPhoneNumber}" />
                    </Style>
                </DataGridComboBoxColumn.ElementStyle>
                <DataGridComboBoxColumn.EditingElementStyle>
                    <Style TargetType="{x:Type ComboBox}">
                        <Setter Property="ItemsSource" Value="{Binding PhoneNumbers}" />
                        <Setter Property="SelectedValue" Value="{Binding SelectedPhoneNumber}" />
                    </Style>
                </DataGridComboBoxColumn.EditingElementStyle>

            </DataGridComboBoxColumn>
            </DataGrid.Columns>
        </DataGrid>


    </Grid>
</Window>

// code behind

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace DataGridTest
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {

        public ObservableCollection<Person> PersonList { get; set; }

        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;

            PersonList = new ObservableCollection<Person>();

            Person jjim = new Person() { FirstName = "jimmy", LastName = "jim" };

            jjim.PhoneNumbers.Add("123-4567");
            jjim.PhoneNumbers.Add("234-5678");

            Person mmark = new Person() { FirstName = "mike", LastName = "mark" };

            mmark.PhoneNumbers.Add("345-6789");
            mmark.PhoneNumbers.Add("456-7890");

            PersonList.Add(jjim);
            PersonList.Add(mmark);
        }


    }

    public class Person : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;


        public ObservableCollection<string> PhoneNumbers { get; set; }



    private string selectedPhoneNumber; 
    public string SelectedPhoneNumber
    {
        get
        {
            return this.selectedPhoneNumber; 
        }

        set
        {
            this.selectedPhoneNumber = value;
            RaisePropertyChanged("SelectedPhoneNumber");
        }
    }


        public Person()
        {
            PhoneNumbers = new ObservableCollection<string>(); 
        }

        private void RaisePropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        private string firstName;
        private string lastName;

        public string FirstName
        {
            get
            {
                return this.firstName;
            }

            set
            {
                this.firstName = value;
                RaisePropertyChanged("FirstName");
            }
        }

        public string LastName
        {
            get
            {
                return this.lastName;
            }

            set
            {
                this.lastName = value;
                RaisePropertyChanged("LastName");
            }
        }
    }

}

Answer 1

A DataGridColumn is not a visual element and doesn't have a DataContext and therefore your binding won't work. You could easily fix this by specifying an ElementStyle and and EditingElementStyle for the DataGridComboBoxColumn:

<DataGridComboBoxColumn Header="Phone Number">
    <DataGridComboBoxColumn.ElementStyle>
        <Style TargetType="{x:Type ComboBox}">
            <Setter Property="ItemsSource" Value="{Binding PhoneNumbers}" />
        </Style>
    </DataGridComboBoxColumn.ElementStyle>
    <DataGridComboBoxColumn.EditingElementStyle>
        <Style TargetType="{x:Type ComboBox}">
            <Setter Property="ItemsSource" Value="{Binding PhoneNumbers}" />
        </Style>
    </DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>

This works because the actual ComboBox element that eventually gets added to the visual tree by the DataGridComboBoxColumn and that the styles are getting applied to always has a DataContext.

Please refer to the following link for more examples of how to data bind to a ComboBox in WPF: https://code.msdn.microsoft.com/windowsdesktop/Best-ComboBox-Tutorial-5cc27f82#content

Answer 2

Have a look at my anser to this question: DataGridComboBoxColumn is empty Seems like the same problem. The DataGridComboBoxColumn is a bit buggy.