How to pass selected row's data to a command?
SfDataGrid provides two events for selection: SelectionChanging and SelectionChanged. It provides the added items and the removed items as arguments in it. You can pass the selected row info to a command in the ViewModel by using the Xamarin.Forms.Behaviors.
Refer the below code example in which a custom behavior for passing the selected row information to ViewModel is defined.
<?xml version="1.0" encoding="utf-8" ?> <ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:syncfusion="clr-namespace:Syncfusion.SfDataGrid.XForms;assembly=Syncfusion.SfDataGrid.XForms" xmlns:local="clr-namespace:SelectionSample" x:Class="SelectionSample.MainPage">
<ContentPage.BindingContext> <local:ViewModel x:Name="viewModel" /> </ContentPage.BindingContext>
<ContentPage.Resources> <ResourceDictionary> <local:CustomConverter x:Key="gridSelectionChangedEventArgs" /> </ResourceDictionary> </ContentPage.Resources>
<syncfusion:SfDataGrid x:Name="dataGrid" ColumnSizer="Star" SelectionMode="Single" ItemsSource="{Binding OrderInfo}"> <syncfusion:SfDataGrid.Behaviors> <local:CustomBehavior Command="{Binding SelectionCommand}" Converter="{StaticResource gridSelectionChangedEventArgs}" /> </syncfusion:SfDataGrid.Behaviors> </syncfusion:SfDataGrid> </ContentPage>s |
The below code illustrates the command and the call back implementation to get the selected row information.
public class ViewModel
{
private ICommand selectionCommand;
public ICommand SelectionCommand
{
get { return selectionCommand; }
set { selectionCommand = value; }
}
public ViewModel()
{
selectionCommand = new Command<GridSelectionChangedEventArgs>(OnSelectionChanged);
OrderInfoRepository orderInfoRepository = new OrderInfoRepository();
orderInfo = orderInfoRepository.GetOrderDetails(30);
}
private ObservableCollection<OrderInfo> orderInfo;
public ObservableCollection<OrderInfo> OrderInfo
{
get { return orderInfo; }
set { this.orderInfo = value; }
}
internal void GenerateItemsSource(int count)
{
OrderInfoRepository order = new OrderInfoRepository();
orderInfo = order.GetOrderDetails(count);
}
private void OnSelectionChanged(GridSelectionChangedEventArgs e)
{
var SelectedItem = e.AddedItems;
}
}
The below code illustrates the behavior class implementation for the SfDataGrid.
public class CustomBehavior : Behavior<SfDataGrid>
{
public static readonly BindableProperty CommandProperty = BindableProperty.Create("Command", typeof(ICommand), typeof(CustomBehavior), null);
public static readonly BindableProperty InputConverterProperty = BindableProperty.Create("Converter", typeof(IValueConverter), typeof(CustomBehavior), null);
public ICommand Command
{
get { return (ICommand)GetValue(CommandProperty); }
set { SetValue(CommandProperty, value); }
}
public IValueConverter Converter
{
get { return (IValueConverter)GetValue(InputConverterProperty); }
set { SetValue(InputConverterProperty, value); }
}
public SfDataGrid AssociatedObject { get; private set; }
protected override void OnAttachedTo(SfDataGrid bindable)
{
base.OnAttachedTo(bindable);
AssociatedObject = bindable;
bindable.BindingContextChanged += OnBindingContextChanged;
bindable.SelectionChanged += bindable_SelectionChanged;
}
void bindable_SelectionChanged(object sender, GridSelectionChangedEventArgs e)
{
if (Command == null)
{
return;
}
object parameter = Converter.Convert(e, typeof(object), null, null);
var temp = (parameter as GridSelectionChangedEventArgs).AddedItems;
if (Command.CanExecute(parameter))
{
Command.Execute(parameter);
}
}
protected override void OnDetachingFrom(SfDataGrid bindable)
{
base.OnDetachingFrom(bindable);
bindable.BindingContextChanged -= OnBindingContextChanged;
bindable.SelectionChanged -= bindable_SelectionChanged;
AssociatedObject = null;
}
void OnBindingContextChanged(object sender, EventArgs e)
{
OnBindingContextChanged();
}
protected override void OnBindingContextChanged()
{
base.OnBindingContextChanged();
BindingContext = AssociatedObject.BindingContext;
}
}
Screenshot:
Sample Link: