How to: Initialize the New Item Row with Default Values

• May 27, 2019
• 3 minutes to read

This example demonstrates how to automatically initialize cells displayed within the New Item Row with default values. Handle the TableView.InitNewRow event to do this.

Tip

Topic: Add and Remove Rows

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-initialize-the-new-item-row-with-default-values-e1569.

Window1.xaml.vb

Imports DevExpress.Xpf.Grid
Imports System.Collections.ObjectModel
Imports System.Windows

Namespace DXGrid_NewItemRow
    Partial Public Class Window1
        Inherits Window

        Public Sub New()
            InitializeComponent()
            Me.DataContext = New MyViewModel()
        End Sub


        Private Sub TableView_InitNewRow(ByVal sender As Object, ByVal e As InitNewRowEventArgs)
            grid.SetCellValue(e.RowHandle, "UnitPrice", 10)
            grid.SetCellValue(e.RowHandle, "CompanyName", "newcompany")
            grid.SetCellValue(e.RowHandle, "Discontinued", False)
        End Sub

        Private Sub TableView_ValidateRow(ByVal sender As Object, ByVal e As GridRowValidationEventArgs)
            If e.Row Is Nothing Then
                Return
            End If
            If e.RowHandle = GridControl.NewItemRowHandle Then
                e.IsValid = Not String.IsNullOrEmpty(CType(e.Row, Person).ProductName)
                e.Handled = True
            End If
        End Sub

        Private Sub TableView_InvalidRowException(ByVal sender As Object, ByVal e As InvalidRowExceptionEventArgs)
            If e.RowHandle = GridControl.NewItemRowHandle Then
                e.ErrorText = "Please enter the Product name. "
                e.WindowCaption = "Input Error"
            End If
        End Sub
    End Class

    Public Class MyViewModel
        Public Sub New()
            CreateList()
        End Sub

        Public Property PersonList() As ObservableCollection(Of Person)
        Private Sub CreateList()
            PersonList = New ObservableCollection(Of Person)()
            For i As Integer = 0 To 2
                Dim p As New Person(i)
                PersonList.Add(p)
            Next i
        End Sub
    End Class
    Public Class Person
        Public Sub New()
        End Sub
        Public Sub New(ByVal i As Integer)
            ProductName = "ProductName" & i
            CompanyName = "CompanyName" & i
            UnitPrice = i
            Discontinued = i Mod 2 = 0
        End Sub

        Public Property ProductName() As String

        Public Property CompanyName() As String

        Public Property UnitPrice() As Integer

        Public Property Discontinued() As Boolean
    End Class
End Namespace

Window1.xaml

<Window x:Class="DXGrid_NewItemRow.Window1" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid" 
        Title="Window1" Height="300" Width="481">
    <Grid>
        <dxg:GridControl x:Name="grid" AutoGenerateColumns="AddNew" ItemsSource="{Binding PersonList}">
            <dxg:GridControl.View>
                <dxg:TableView x:Name="view" AutoWidth="True" 
                               NewItemRowPosition="Top" 
                               InitNewRow="TableView_InitNewRow"
                               ValidateRow="TableView_ValidateRow" 
                               InvalidRowException="TableView_InvalidRowException" />
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>

Application.xaml

<Application x:Class="DXGrid_NewItemRow.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" StartupUri="Window1.xaml">
    <Application.Resources>

    </Application.Resources>
</Application>

Application.xaml.vb

Imports System
Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data
Imports System.Linq
Imports System.Windows

Namespace DXGrid_NewItemRow
    ''' <summary>
    ''' Interaction logic for App.xaml
    ''' </summary>
    Partial Public Class App
        Inherits Application

    End Class
End Namespace

Window1.xaml.cs

using DevExpress.Xpf.Grid;
using System.Collections.ObjectModel;
using System.Windows;

namespace DXGrid_NewItemRow {
    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();
            this.DataContext = new MyViewModel();
        }


        private void TableView_InitNewRow(object sender, InitNewRowEventArgs e) {
            grid.SetCellValue(e.RowHandle, "UnitPrice", 10);
            grid.SetCellValue(e.RowHandle, "CompanyName", "newcompany");
            grid.SetCellValue(e.RowHandle, "Discontinued", false);
        }

        private void TableView_ValidateRow(object sender, GridRowValidationEventArgs e) {
            if (e.Row == null) return;
            if (e.RowHandle == GridControl.NewItemRowHandle) {
                e.IsValid = !string.IsNullOrEmpty(((Person)e.Row).ProductName);
                e.Handled = true;
            }
        }

        private void TableView_InvalidRowException(object sender, InvalidRowExceptionEventArgs e) {
            if (e.RowHandle == GridControl.NewItemRowHandle) {
                e.ErrorText = "Please enter the Product name. ";
                e.WindowCaption = "Input Error";
            }
        }
    }

    public class MyViewModel {
        public MyViewModel() {
            CreateList();
        }

        public ObservableCollection<Person> PersonList { get; set; }
        void CreateList() {
            PersonList = new ObservableCollection<Person>();
            for (int i = 0; i < 3; i++) {
                Person p = new Person(i);
                PersonList.Add(p);
            }
        }
    }
    public class Person {
        public Person() { }
        public Person(int i) {
            ProductName = "ProductName" + i;
            CompanyName = "CompanyName" + i;
            UnitPrice = i;
            Discontinued = i % 2 == 0;
        }

        public string ProductName { get; set; }

        public string CompanyName { get; set; }

        public int UnitPrice { get; set; }

        public bool Discontinued { get; set; }
    }
}