Visual Studio/WPF > DataGrid > Error:itemssource를 사용하기 전에 items 컬렉션이 비어 있어야 합니다.

Windows 7 Pro (32bit)
Microsoft Visual Studio 2017 Community
Sublime Text 2

<Window x:Class="_170421_t1510_WpfDataGridComboBox.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:_170421_t1510_WpfDataGridComboBox"
        xmlns:sys="clr-namespace:System;assembly=mscorlib" 
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">

    <Grid>
        <DataGrid x:Name="dataGridView1" HorizontalAlignment="Left" Height="211" Margin="10,10,0,0" VerticalAlignment="Top" Width="497">
            <DataGridTemplateColumn>
                <DataGridTemplateColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                    </Style>
                </DataGridTemplateColumn.HeaderStyle>
                <DataGridTemplateColumn.HeaderTemplate>
                    <DataTemplate>
                        <StackPanel>
                            <TextBlock Text="名前"/>
                        </StackPanel>
                    </DataTemplate>
                </DataGridTemplateColumn.HeaderTemplate>
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <StackPanel>
                            <TextBlock Text="{Binding Name}"/>
                        </StackPanel>
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>
        </DataGrid>

    </Grid>
</Window>

using System;
using System.Collections.Generic;
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 _170421_t1510_WpfDataGridComboBox
{
    /// <summary>
    /// MainWindow.xaml の相互作用ロジック
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            List<User> users = new List<User>();
            users.Add(new User() { Name = "7of9", Gender = "Women" });
            users.Add(new User() { Name = "Chakotay", Gender = "Men" });
            users.Add(new User() { Name = "Odo", Gender = "None" });
            dataGridView1.ItemsSource = users;
        }
    }
    public class User
    {
        public string Name { get; set; }
        public string Gender { get; set; }
    }
    public enum Gender
    {
        None,
        Men,
        Women,
    }
    public class GenderComboBoxItem
    {
        public string Label { get; set; }
        public Gender Value { get; set; }
    }
}

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