Data Grid for WPF - How to Pause Data Updates in the Edit Form

This example illustartates how to pause data updates when a user edits a row in the Edit Form. To do that, handle the RowEditStarted and RowEditFinished events. Alternatively, you can create commands in a View Model and bind them to the RowEditStartedCommand and RowEditFinishedCommand properties.

In this example, the GridControl updates data on a timer. The UpdateRows() function updates data depending on the updatesLocker value. When a user starts to edit a row, the RowEditStarted event occurs. The event handler sets the updatesLocker value to true to lock data updates. When the user finished editing the row, RowEditFinished occurs and the event handler unlocks updates.

C#
bool updatesLocker;  
// ...  
private void OnRowEditStarted(object sender, RowEditStartedEventArgs e) => Volatile.Write(ref updatesLocker, true);  

private void OnRowEditFinished(object sender, RowEditFinishedEventArgs e) => Volatile.Write(ref updatesLocker, false);  

void UpdateRows(object parameter) {  
    if(!Volatile.Read(ref updatesLocker)) {  
        var row = data[random.Next(0, data.Count)];  
        if(row.ShouldUpdate) {  
            row.Value = random.Next(1, 100);  
        }  
    }  
}

In the TreeListView, use the following events and properties:

Files to Look At

Code-Behind

MainViewModel.xaml.cs (MainViewModel.xaml.vb)
MainWindow.xaml (MainWindow.xaml)

Documentation

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Example Code

LockOnRowEdit_CodeBehind/MainWindow.xaml.cs(vb)

C#
VB.NET

C#
using DevExpress.Mvvm;
using DevExpress.Xpf.Grid;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Windows;

namespace LockOnRowEdit_CodeBehind {
    public class DataItem : BindableBase {
        public int Id { get => GetValue<int>(); set => SetValue(value); }
        public string Name { get => GetValue<string>(); set => SetValue(value); }
        public int Value { get => GetValue<int>(); set => SetValue(value); }
        public bool ShouldUpdate { get => GetValue<bool>(); set => SetValue(value); }

        public DataItem(Random random, int id) {
            Id = id;
            Name = $"Item {id}";
            Value = random.Next(1, 100);
            ShouldUpdate = true;
        }
    }
    public partial class MainWindow : Window {
        List<DataItem> data;

        Timer updateTimer;

        bool updatesLocker;

        Random random;

        public MainWindow() {
            InitializeComponent();
            random = new Random();
            grid.ItemsSource = data = new List<DataItem>(Enumerable.Range(0, 20).Select(i => new DataItem(random, i)));
            updateTimer = new Timer(UpdateRows, null, 0, 1);
        }

        private void OnRowEditStarted(object sender, RowEditStartedEventArgs e) => Volatile.Write(ref updatesLocker, true);

        private void OnRowEditFinished(object sender, RowEditFinishedEventArgs e) => Volatile.Write(ref updatesLocker, false);

        void UpdateRows(object parameter) {
            if(!Volatile.Read(ref updatesLocker)) {
                var row = data[random.Next(0, data.Count)];
                if(row.ShouldUpdate) {
                    row.Value = random.Next(1, 100);
                }
            }
        }
    }
}

Visual Basic
Imports DevExpress.Mvvm
Imports DevExpress.Xpf.Grid
Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Threading
Imports System.Windows

Namespace LockOnRowEdit_CodeBehind

    Public Class DataItem
        Inherits BindableBase

        Public Property Id As Integer
            Get
                Return GetValue(Of Integer)()
            End Get

            Set(ByVal value As Integer)
                SetValue(value)
            End Set
        End Property

        Public Property Name As String
            Get
                Return GetValue(Of String)()
            End Get

            Set(ByVal value As String)
                SetValue(value)
            End Set
        End Property

        Public Property Value As Integer
            Get
                Return GetValue(Of Integer)()
            End Get

            Set(ByVal value As Integer)
                SetValue(value)
            End Set
        End Property

        Public Property ShouldUpdate As Boolean
            Get
                Return GetValue(Of Boolean)()
            End Get

            Set(ByVal value As Boolean)
                SetValue(value)
            End Set
        End Property

        Public Sub New(ByVal random As Random, ByVal id As Integer)
            Me.Id = id
            Name = $"Item {id}"
            Value = random.Next(1, 100)
            ShouldUpdate = True
        End Sub
    End Class

    Public Partial Class MainWindow
        Inherits Window

        Private data As List(Of DataItem)

        Private updateTimer As Timer

        Private updatesLocker As Boolean

        Private random As Random

        Public Sub New()
            Me.InitializeComponent()
            random = New Random()
            data = New List(Of DataItem)(Enumerable.Range(0, 20).[Select](Function(i) New DataItem(random, i)))
            Me.grid.ItemsSource = data
            updateTimer = New Timer(AddressOf UpdateRows, Nothing, 0, 1)
        End Sub

        Private Sub OnRowEditStarted(ByVal sender As Object, ByVal e As RowEditStartedEventArgs)
            Volatile.Write(updatesLocker, True)
        End Sub

        Private Sub OnRowEditFinished(ByVal sender As Object, ByVal e As RowEditFinishedEventArgs)
            Volatile.Write(updatesLocker, False)
        End Sub

        Private Sub UpdateRows(ByVal parameter As Object)
            If Not Volatile.Read(updatesLocker) Then
                Dim row = data(random.Next(0, data.Count))
                If row.ShouldUpdate Then
                    row.Value = random.Next(1, 100)
                End If
            End If
        End Sub
    End Class
End Namespace

LockOnRowEdit_CodeBehind/MainWindow.xaml

XAML
<Window x:Class="LockOnRowEdit_CodeBehind.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:LockOnRowEdit_CodeBehind"
        xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <dxg:GridControl x:Name="grid" AutoGenerateColumns="AddNew">
            <dxg:GridControl.View>
                <dxg:TableView x:Name="view" EditFormShowMode="Inline" RowEditStarted="OnRowEditStarted" RowEditFinished="OnRowEditFinished"/>
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>

LockOnRowEdit_MVVM/MainViewModel.cs(vb)

C#
VB.NET

C#
using DevExpress.Mvvm;
using DevExpress.Mvvm.DataAnnotations;
using DevExpress.Mvvm.Xpf;
using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Threading;
using System.Windows.Threading;

namespace LockOnRowEdit_MVVM {
    public class DataItem : BindableBase {
        public int Id { get => GetValue<int>(); set => SetValue(value); }
        public string Name { get => GetValue<string>(); set => SetValue(value);}
        public int Value { get => GetValue<int>(); set => SetValue(value); }
        public bool ShouldUpdate { get => GetValue<bool>(); set => SetValue(value); }

        public DataItem(Random random, int id) {
            Id = id;
            Name = $"Item {id}";
            Value = random.Next(1, 100);
            ShouldUpdate = true;
        }
    }
    public class MainViewModel : ViewModelBase {
        public ObservableCollection<DataItem> Data { get => GetValue<ObservableCollection<DataItem>>(); set => SetValue(value); }

        Random random;

        Timer updateTimer;

        bool updatesLocker;

        public MainViewModel() {
            random = new Random();
            Data = new ObservableCollection<DataItem>(Enumerable.Range(0, 20).Select(i => new DataItem(random, i)));
            updateTimer = new Timer(UpdateRows, null, 0, 1);
        }

        [Command]
        public void LockUpdates(RowEditStartedArgs args) => Volatile.Write(ref updatesLocker, true);

        [Command]
        public void UnlockUpdates(RowEditFinishedArgs args) => Volatile.Write(ref updatesLocker, false);

        void UpdateRows(object parameter) {
            if(!Volatile.Read(ref updatesLocker)) {
                var row = Data[random.Next(0, Data.Count)];
                if(row.ShouldUpdate) {
                    row.Value = random.Next(1, 100);
                }
            }
        }
    }
}

Visual Basic
Imports DevExpress.Mvvm
Imports DevExpress.Mvvm.DataAnnotations
Imports DevExpress.Mvvm.Xpf
Imports System
Imports System.Collections.ObjectModel
Imports System.ComponentModel
Imports System.Linq
Imports System.Threading

Namespace LockOnRowEdit_MVVM

    Public Class DataItem
        Inherits BindableBase

        Public Property Id As Integer
            Get
                Return GetValue(Of Integer)()
            End Get

            Set(ByVal value As Integer)
                SetValue(value)
            End Set
        End Property

        Public Property Name As String
            Get
                Return GetValue(Of String)()
            End Get

            Set(ByVal value As String)
                SetValue(value)
            End Set
        End Property

        Public Property Value As Integer
            Get
                Return GetValue(Of Integer)()
            End Get

            Set(ByVal value As Integer)
                SetValue(value)
            End Set
        End Property

        Public Property ShouldUpdate As Boolean
            Get
                Return GetValue(Of Boolean)()
            End Get

            Set(ByVal value As Boolean)
                SetValue(value)
            End Set
        End Property

        Public Sub New(ByVal random As Random, ByVal id As Integer)
            Me.Id = id
            Name = $"Item {id}"
            Value = random.Next(1, 100)
            ShouldUpdate = True
        End Sub
    End Class

    Public Class MainViewModel
        Inherits ViewModelBase

        Public Property Data As ObservableCollection(Of DataItem)
            Get
                Return GetValue(Of ObservableCollection(Of DataItem))()
            End Get

            Set(ByVal value As ObservableCollection(Of DataItem))
                SetValue(value)
            End Set
        End Property

        Private random As Random

        Private updateTimer As Timer

        Private updatesLocker As Boolean

        Public Sub New()
            random = New Random()
            Data = New ObservableCollection(Of DataItem)(Enumerable.Range(0, 20).[Select](Function(i) New DataItem(random, i)))
            updateTimer = New Timer(AddressOf UpdateRows, Nothing, 0, 1)
        End Sub

        <Command>
        Public Sub LockUpdates(ByVal args As RowEditStartedArgs)
            Volatile.Write(updatesLocker, True)
        End Sub

        <Command>
        Public Sub UnlockUpdates(ByVal args As RowEditFinishedArgs)
            Volatile.Write(updatesLocker, False)
        End Sub

        Private Sub UpdateRows(ByVal parameter As Object)
            If Not Volatile.Read(updatesLocker) Then
                Dim row = Data(random.Next(0, Data.Count))
                If row.ShouldUpdate Then
                    row.Value = random.Next(1, 100)
                End If
            End If
        End Sub
    End Class
End Namespace

LockOnRowEdit_MVVM/MainWindow.xaml

XAML
<Window x:Class="LockOnRowEdit_MVVM.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:LockOnRowEdit_MVVM"
        xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
        xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.DataContext>
        <local:MainViewModel/>
    </Window.DataContext>
    <Grid>
        <dxg:GridControl AutoGenerateColumns="AddNew" ItemsSource="{Binding Data}">
            <dxg:GridControl.View>
                <dxg:TableView EditFormShowMode="Inline" RowEditStartedCommand="{Binding LockUpdatesCommand}" RowEditFinishedCommand="{Binding UnlockUpdatesCommand}"/>
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>

DevExpress Support Team

last modified 3 years ago

Modified: November 8, 2021 12:08 PM

Platform: WPF

Product: DXGrid and DXTreeList for WPF

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