How to clean data from datagrid

Question

I've got a problem with my WPF app. Could someone tell me how to clean data from dataGrid? Ive tried this:

loading data to dataGrid:

this.dataGrid.ItemsSource = dataFromDB;

and Im trying to clear dataGrid using some Button:

        private void clearGrid_Click(object sender, RoutedEventArgs e)
        {
            dataGrid.Items.Clear(); 
            dataGrid.Items.Refresh();
        }

and this doesn't work. Could someone help me where is bug?

Answer 1

You could bind to a property something like

<Window x:Class="WpfApp1.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:WpfApp1"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800"
        DataContext="{Binding RelativeSource={RelativeSource Self}}">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <Button Content="Clear" Click="ButtonBase_OnClick"></Button>
        <DataGrid Grid.Row="1" ItemsSource="{Binding People}" >
            <DataGrid.Columns>
                <DataGridTextColumn Header="Name" Binding="{Binding Name}"></DataGridTextColumn>
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
</Window>



using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;
using WpfApp1.Annotations;

namespace WpfApp1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        private ObservableCollection<Person> _people;

        public ObservableCollection<Person> People
        {
            get => _people;
            set
            {
                _people = value;
                OnPropertyChanged();
            }
        }

        public MainWindow()
        {
            InitializeComponent();

            People = new ObservableCollection<Person>();

            People.Add(new Person(){Id = 1, Name = "Jane"});
            People.Add(new Person(){Id = 2, Name = "John"});
        }

        public event PropertyChangedEventHandler PropertyChanged;

        [NotifyPropertyChangedInvocator]
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
        {
            People.Clear();
        }
    }

    public class Person
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }
}