WPF DataGrid CheckBox Checked and Unchecked event binding to command in mvvm via behavior:InvokeCommandAction
//Key code //xaml <DataGridTemplateColumn Header="Select"> <DataGridTemplateColumn.CellTemplate> <DataTemplate> <CheckBox x:Name="isSelectedCbx" IsThreeState="False" > <behavior:Interaction.Triggers> <behavior:EventTrigger EventName="Checked"> <behavior:InvokeCommandAction Command="{Binding RelativeSource={RelativeSource AncestorType={x:Type Window}},Path=DataContext.DataGridRowCheckedCmd}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=DataGridRow}}"/> </behavior:EventTrigger> <behavior:EventTrigger EventName="Unchecked"> <behavior:InvokeCommandAction Command="{Binding RelativeSource={RelativeSource AncestorType={x:Type Window}},Path=DataContext.DataGridRowUnCheckedCmd}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=DataGridRow}}"/> </behavior:EventTrigger> </behavior:Interaction.Triggers> </CheckBox> </DataTemplate> </DataGridTemplateColumn.CellTemplate> </DataGridTemplateColumn> //cs private void InitCmds() { ExportAllCmd = new DelCmd(ExportAllCmdExecuted); ExportSelectedCmd = new DelCmd(ExportSelectedCmdExecuted); SelectedCmd = new DelCmd(SelectedCmdExecuted); DataGridRowCheckedCmd = new DelCmd(DataGridRowCheckedCmdExecuted); DataGridRowUnCheckedCmd = new DelCmd(DataGridRowUnCheckedCmdExecuted); } private void DataGridRowUnCheckedCmdExecuted(object obj) { var row = obj as DataGridRow; if (row != null) { var bk = row.Item as Book; if (SelectedBooksCollection != null && bk != null && SelectedBooksCollection.Contains(bk)) { SelectedBooksCollection.Remove(bk); } } } private void DataGridRowCheckedCmdExecuted(object obj) { var row = obj as DataGridRow; if (row != null) { var bk = row.Item as Book; if (SelectedBooksCollection != null && bk != null && !SelectedBooksCollection.Contains(bk)) { SelectedBooksCollection.Add(bk); } } }
//Whole code
<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:behavior="http://schemas.microsoft.com/xaml/behaviors" xmlns:local="clr-namespace:WpfApp1" mc:Ignorable="d" WindowState="Maximized" Title="MainWindow" Height="450" Width="800"> <Window.Resources> <Style TargetType="DataGridRow"> <Setter Property="FontSize" Value="20"/> <Style.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter Property="FontSize" Value="30"/> </Trigger> </Style.Triggers> </Style> </Window.Resources> <Grid> <Grid.RowDefinitions> <RowDefinition Height="50"/> <RowDefinition/> </Grid.RowDefinitions> <ToolBar Grid.Row="0"> <Button Content="Export Selected" Command="{Binding ExportSelectedCmd}" CommandParameter="{Binding ElementName=dg}"/> <Button Content="Export All" Command="{Binding ExportAllCmd}" CommandParameter="{Binding ElementName=dg}"/> </ToolBar> <DataGrid Grid.Row="1" x:Name="dg" ItemsSource="{Binding BooksCollection,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" AutoGenerateColumns="False" SelectionMode="Extended" CanUserAddRows="False" SelectedItem="{Binding SelectedBook,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"> <!--<behavior:Interaction.Triggers> <behavior:EventTrigger EventName="SelectionChanged"> <behavior:InvokeCommandAction Command="{Binding SelectedCmd}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=DataGrid}}"/> </behavior:EventTrigger> </behavior:Interaction.Triggers>--> <DataGrid.Columns> <DataGridTemplateColumn Header="Select"> <DataGridTemplateColumn.CellTemplate> <DataTemplate> <CheckBox x:Name="isSelectedCbx" IsThreeState="False" > <behavior:Interaction.Triggers> <behavior:EventTrigger EventName="Checked"> <behavior:InvokeCommandAction Command="{Binding RelativeSource={RelativeSource AncestorType={x:Type Window}},Path=DataContext.DataGridRowCheckedCmd}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=DataGridRow}}"/> </behavior:EventTrigger> <behavior:EventTrigger EventName="Unchecked"> <behavior:InvokeCommandAction Command="{Binding RelativeSource={RelativeSource AncestorType={x:Type Window}},Path=DataContext.DataGridRowUnCheckedCmd}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=DataGridRow}}"/> </behavior:EventTrigger> </behavior:Interaction.Triggers> </CheckBox> </DataTemplate> </DataGridTemplateColumn.CellTemplate> </DataGridTemplateColumn> <DataGridTextColumn Header="Id" Binding="{Binding Id}"/> <DataGridTextColumn Header="Name" Binding="{Binding Name}"/> <DataGridTextColumn Header="Title" Binding="{Binding Title}"/> </DataGrid.Columns> </DataGrid> </Grid> </Window> //cs 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; using Microsoft.Win32; using Newtonsoft.Json; using System.IO; namespace WpfApp1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); var vm = new BookVM(); this.DataContext = vm; } } public class BookVM : INotifyPropertyChanged { public BookVM() { InitData(); InitCmds(); } private void InitCmds() { ExportAllCmd = new DelCmd(ExportAllCmdExecuted); ExportSelectedCmd = new DelCmd(ExportSelectedCmdExecuted); SelectedCmd = new DelCmd(SelectedCmdExecuted); DataGridRowCheckedCmd = new DelCmd(DataGridRowCheckedCmdExecuted); DataGridRowUnCheckedCmd = new DelCmd(DataGridRowUnCheckedCmdExecuted); } private void DataGridRowUnCheckedCmdExecuted(object obj) { var row = obj as DataGridRow; if (row != null) { var bk = row.Item as Book; if (SelectedBooksCollection != null && bk != null && SelectedBooksCollection.Contains(bk)) { SelectedBooksCollection.Remove(bk); } } } private void DataGridRowCheckedCmdExecuted(object obj) { var row = obj as DataGridRow; if (row != null) { var bk = row.Item as Book; if (SelectedBooksCollection != null && bk != null && !SelectedBooksCollection.Contains(bk)) { SelectedBooksCollection.Add(bk); } } } private void SelectedCmdExecuted(object obj) { var dg = obj as DataGrid; if (dg != null) { var selItems = dg.SelectedItems; } } private void ExportSelectedCmdExecuted(object obj) { var dg = obj as DataGrid; if (dg != null && SelectedBooksCollection!=null && SelectedBooksCollection.Any()) { var selectedJson = JsonConvert.SerializeObject(SelectedBooksCollection, Formatting.Indented); WriteJsoToFile(selectedJson); } } private void WriteJsoToFile(string jsonStr) { SaveFileDialog dialog = new SaveFileDialog(); dialog.Filter = "Json Files|*.json|All Files|*.*"; if(dialog.ShowDialog()==true) { File.AppendAllText(dialog.FileName, jsonStr); } } private void ExportAllCmdExecuted(object obj) { var dg = obj as DataGrid; if (dg != null && dg.Items!=null) { string allJson = JsonConvert.SerializeObject(dg.Items, Formatting.Indented); WriteJsoToFile(allJson); } } private void InitData() { BooksCollection = new ObservableCollection<Book>(); for (int i = 0; i < 1000000; i++) { BooksCollection.Add(new Book() { Id = i + 1, Name = $"Name_{i + 1}", Title = $"Title_{i + 1}" }); } SelectedBooksCollection = new ObservableCollection<Book>(); } public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propName) { var handler = PropertyChanged; if (handler != null) { handler?.Invoke(this, new PropertyChangedEventArgs(propName)); } } public DelCmd ExportSelectedCmd { get; set; } public DelCmd ExportAllCmd { get; set; } public DelCmd SelectedCmd { get; set; } public DelCmd DataGridRowCheckedCmd { get; set; } public DelCmd DataGridRowUnCheckedCmd { get; set; } private ObservableCollection<Book> booksCollection; public ObservableCollection<Book> BooksCollection { get { return booksCollection; } set { if (value != booksCollection) { booksCollection = value; OnPropertyChanged(nameof(BooksCollection)); } } } private Book selectedBook; public Book SelectedBook { get { return selectedBook; } set { if (value != selectedBook) { selectedBook = value; OnPropertyChanged(nameof(SelectedBook)); } } } private ObservableCollection<Book> selectedBooksCollection; public ObservableCollection<Book> SelectedBooksCollection { get { return selectedBooksCollection; } set { if (value != selectedBooksCollection) { selectedBooksCollection = value; OnPropertyChanged(nameof(SelectedBooksCollection)); } } } } public class Book { public int Id { get; set; } public string Name { get; set; } public string Title { get; set; } } public class DelCmd : ICommand { private Action<object> execute; private Predicate<object> canExecute; public DelCmd(Action<object> executeValue, Predicate<object> canExecuteValue) { execute = executeValue; canExecute = canExecuteValue; } public DelCmd(Action<object> executeValue) : this(executeValue, null) { } public event EventHandler CanExecuteChanged { add { CommandManager.RequerySuggested += value; } remove { CommandManager.RequerySuggested -= value; } } public bool CanExecute(object parameter) { if (canExecute == null) { return true; } return canExecute(parameter); } public void Execute(object parameter) { execute(parameter); } } }
