Binding to a Collection of Selected Items

• Feb 11, 2022
• 4 minutes to read

This topic describes how to bind the GridControl‘s selection to a collection of items defined in a Model or View Model. You also will learn how to bind a control to the GridControl‘s selection.

Bind GridControl Selection to a Collection in a View Model

The following code sample shows how to synchronize the GridControl‘s selection with an item collection in a View Model. The code sample:

1. Binds the GridControl‘s SelectedItems property to a Selection collection defined in a View Model.
2. Adds a button that deletes selected rows.

XAML

<Window.DataContext>
    <local:CustomersViewModel/>
</Window.DataContext>
<Button Command="{Binding DeleteSelectedRowsCommand}" Content="Delete Selected Rows"/>
<dxg:GridControl ItemsSource="{Binding Customers}" 
                 SelectionMode="Row" 
                 SelectedItems="{Binding Selection}"
                 ... />

The view model includes the following classes and collections:

• Customer - a data object that contains customer information (name, city, number of visits, birthday).
• CustomerDataModel - the customer data model that populates the Customers collection with data.
• CustomersViewModel - the customer view model.
• Customers - a collection of customers displayed in the GridControl.
• Selection - a collection of GridControl selected items.
• DeleteSelectedRowsCommand - the command that deletes selected items from the GridControl.

View Example

C#

using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using DevExpress.Mvvm;

namespace WPFGridMVVMSelection {
    public class Customer : BindableBase {
        public string Name { get; set; }
        public string City { get; set; }
        public int Visits { get; set; }
        public DateTime? Birthday { get; set; }
    }
    public class CustomersDataModel {
        public static IList<Customer> GetCustomers() {
            ObservableCollection<Customer> people = new ObservableCollection<Customer> { ... };
            return people;
        }
    }
    public class CustomersViewModel : ViewModelBase {
        public CustomersViewModel() {
            DeleteSelectedRowsCommand = new DelegateCommand(DeleteSelectedRows, CanDeleteSelectedRows);
        }
        public IList<Customer> Customers { get; } = CustomersDataModel.GetCustomers();
        public ObservableCollection<Customer> Selection { get; } = new ObservableCollection<Customer>();
        public DelegateCommand DeleteSelectedRowsCommand { get; private set; }
        void DeleteSelectedRows() {
            Selection.ToList().ForEach(item => Customers.Remove(item));
        }
        bool CanDeleteSelectedRows() {
            return Selection.Count > 0;
        }
    }
}

VB.NET

Imports System
Imports System.Linq
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Imports DevExpress.Mvvm

Namespace WPFGridMVVMSelection
    Public Class Customer
        Inherits BindableBase

        Public Property Name As String
        Public Property City As String
        Public Property Visits As Integer
        Public Property Birthday As DateTime?
    End Class

    Public Class CustomersDataModel
        Public Shared Function GetCustomers() As IList(Of Customer)
            Dim people As ObservableCollection(Of Customer) = New ObservableCollection(Of Customer) From {
                New Customer() With { ... }
            Return people
        End Function
    End Class

    Public Class CustomersViewModel
        Inherits ViewModelBase

        Public Sub New()
            DeleteSelectedRowsCommand = New DelegateCommand(AddressOf DeleteSelectedRows, AddressOf CanDeleteSelectedRows)
        End Sub

        Public ReadOnly Property Customers As IList(Of Customer) = CustomersDataModel.GetCustomers()
        Public ReadOnly Property Selection As ObservableCollection(Of Customer) = New ObservableCollection(Of Customer)()
        Public Property DeleteSelectedRowsCommand As DelegateCommand

        Private Sub DeleteSelectedRows()
            Selection.ToList().ForEach(Sub(item) Customers.Remove(item))
        End Sub

        Private Function CanDeleteSelectedRows() As Boolean
            Return Selection.Count > 0
        End Function
    End Class
End Namespace

Bind ListBoxEdit Items to GridControl Selection

The following code sample binds the ListBoxEdit to the DataControlBase.SelectedItems collection to show the GridControl‘s selected rows in the ListBox:

XAML

<dxg:GridControl x:Name="grid" SelectionMode="Row" ... />
<GroupBox Header="Selected Records">
    <dxe:ListBoxEdit ItemsSource="{Binding SelectedItems, ElementName=grid}"
                     DisplayMember="Name"/>
</GroupBox>

Notes and Limitations

• In Multiple Row Selection mode, the GridControl‘s DataControlBase.SelectedItems collection is populated with items in the same order rows/nodes are selected.

  

• When the GridControl works in the Server Mode or with Virtual Sources, the DataControlBase.SelectedItems collection returns an empty list. Use the DataControlBase.GetSelectedRowHandles and DataControlBase.GetRow / DataControlBase.GetRowAsync methods to obtain row handles and data items.

• When you work with the master-detail GridControl, the DataControlBase.SelectedItems collection contains items only from the master GridControl. To obtain selected detail records in a DataControlDetailDescriptor:

  1. Use the detail GridControl‘s DataControlBase.GetSelectedRowHandles method.
  2. Pass row handles to the GridControl.GetRow / DataControlBase.GetRowAsync method to obtain row data items.

• To get selected nodes ordered by visible indexes, use the TreeListControlBase.GetSelectedNodes method. To get row handles of selected items ordered by visible indexes, use the DataControlBase.GetSelectedRowHandles method.