在WPF中使用計時器刷新數據網格后，如何保持我對數據網格行的選擇

Question

我有WPF DataGrid，並且正在綁定DataGrid，但是如果對Data進行了任何更改，它將自動刷新，但是我對datagrid行的選擇將未被選中。

Answer 1

與其使用List來存儲數據， ObservableCollection嘗試使用ObservableCollection 。 使用ObservableCollection的好處是，每當您向集合中添加項目時，UI都會自動更新，因此不需要手動刷新DataGrid 。 下面，我共享了一個示例應用程序，該應用程序添加和更新了DataGrid記錄。

XAML：

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    <StackPanel Orientation="Horizontal">
        <RadioButton Name="CBAdd" GroupName="AddOrEdit" Content="Add Messages" IsChecked="True"></RadioButton>
        <RadioButton Name="CBUpdate" GroupName="AddOrEdit" Content="Update Messages"></RadioButton>
    </StackPanel>
    <DataGrid Grid.Row="1" Name="DGNew" CanUserAddRows="False">

    </DataGrid>
</Grid>

背后的代碼：

using System;
using System.Windows;
using System.Timers;
using System.Collections.ObjectModel;
using System.Windows.Threading;
using System.ComponentModel;

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        Timer _timer = null;
        ObservableCollection<CustomMessage> _messages = null;

        int count = 0;

        public MainWindow()
        {
            InitializeComponent();
            _messages = new ObservableCollection<CustomMessage>();
            count++;
            _messages.Add(new CustomMessage() { ID = count, Message = "Message" });
            _timer = new Timer(1000);
            _timer.Elapsed += new ElapsedEventHandler(_timer_Elapsed);

            this.DGNew.ItemsSource = _messages;
            _timer.Start();
        }

        void _timer_Elapsed(object sender, ElapsedEventArgs e)
        {
            try
            {
                _timer.Stop();
                Application.Current.Dispatcher.Invoke(DispatcherPriority.Background, new Action(() =>
                {
                    if (this.CBAdd.IsChecked == true)
                    {
                        count++;
                        _messages.Add(new CustomMessage() { ID = count, Message = "Timer Message " + count });
                    }
                    else
                    {
                        // Udpate existing Message
                        Random random = new Random();
                        CustomMessage message = _messages[random.Next(0, count)];
                        message.Message = "Updated Time" + DateTime.Now.ToLongTimeString();
                    }
                }));
            }
            finally
            {
                _timer.Start();
            }
        }
    }

    public class CustomMessage : INotifyPropertyChanged
    {
        private int _ID;

        public int ID
        {
            get { return _ID; }
            set
            {
                _ID = value;
                OnPropertyChanged("ID");
            }
        }

        private string _Message;

        public string Message
        {
            get { return _Message; }
            set
            {
                _Message = value;
                OnPropertyChanged("Message");
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}