Set IsSynchronizedWithCurrentItem = "true".

为了解决您的评论，我假设您的 DataGrid 的 SelectionUnit 设置为Cell"，是吗?好的，我不确定这是否是***解决方案，但您可以做的一件事是处理 DataGrid 的 Loaded 事件并在代码隐藏中手动设置选定的单元格.所以你会有这样的事情:

To address your comment, I assume that your DataGrid's SelectionUnit is set to "Cell", is it? Okay, I'm not sure if this is the best solution but one thing you can do is handle the Loaded event for the DataGrid and manually set the selected cell in the code-behind. So you'll have something like this:

<DataGrid x:Name="dg" AutoGenerateColumns="False" IsSynchronizedWithCurrentItem="True"
            SelectedCellsChanged="dg_SelectedCellsChanged" SelectionUnit="Cell"
            Loaded="dg_Loaded">
    ...
</DataGrid>

事件处理程序:

private void dg_Loaded(object sender, RoutedEventArgs e)
{
    if ((dg.Items.Count > 0) &&
        (dg.Columns.Count > 0))
    {
        //Select the first column of the first item.
        dg.CurrentCell = new DataGridCellInfo(dg.Items[0], dg.Columns[0]);
        dg.SelectedCells.Add(dg.CurrentCell);
    }
}

请注意，这仅在 DataGrid.SelectionUnit 设置为Cell"时才有效.否则，我相信它会抛出异常.

Note that this will only work if the DataGrid.SelectionUnit is set to "Cell". Otherwise, I believe it will throw an exception.

XAML:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <Button Click="Button_Click">Reset</Button>
        <DataGrid x:Name="dg" AutoGenerateColumns="False" IsSynchronizedWithCurrentItem="True"
                SelectionUnit="Cell"
                DataContextChanged="dg_DataContextChanged"
                ItemsSource="{Binding Items}"
                Loaded="dg_Loaded">
            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding}"/>
            </DataGrid.Columns>
        </DataGrid>
    </StackPanel>
</Window>

代码隐藏:

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.LoadItems();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            this.LoadItems();
        }

        private void LoadItems()
        {
            this.DataContext = new { Items = new List<string> { "Item1", "Item2", "Item3" } };
            this.SelectFirstItem();
        }

        private void dg_Loaded(object sender, RoutedEventArgs e)
        {
            SelectFirstItem();
        }

        void SelectFirstItem()
        {
            if ((dg.Items.Count > 0) &&
                (dg.Columns.Count > 0))
            {
                //Select the first column of the first item.
                dg.CurrentCell = new DataGridCellInfo(dg.Items[0], dg.Columns[0]);
                dg.SelectedCells.Add(dg.CurrentCell);
            }
        }

        private void dg_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            this.SelectFirstItem();
        }
    }
}