Per-Pixel Scrolling

• Aug 23, 2018
• 6 minutes to read

To enable per-pixel scrolling, use the property corresponding to the current view:

• CardView.ScrollMode to ScrollMode.Pixel for the CardView
• TableView.AllowPerPixelScrolling to true for the TableView
• TreeListView.AllowPerPixelScrolling to true for the TreeListView

To provide visual effect, set the TableView.AllowScrollAnimation property to true. The TableView.ScrollAnimationMode and TableView.ScrollAnimationDuration properties allow you to customize the animation. The first property specifies the scrolling mode, the second property specifies the animation length. The following modes are available:

• Ease Out

  Starts quickly and then decelerates.

• Ease In/Out

  Starts slowly, accelerates and then decelerates.

• Linear

  Moves smoothly.

• Custom

  Handle the TableView.CustomScrollAnimation event (TreeListView.CustomScrollAnimation in a TreeListView) to provide a custom animation effect.

Tip

In a TreeListView, these properties are: TreeListView.AllowScrollAnimation, TreeListView.ScrollAnimationMode and TreeListView.ScrollAnimationDuration.

Note

If per-pixel scrolling is enabled and rows have different heights, the last (bottom) visible row may not be displayed entirely. Because of the UI virtualization, the GridControl does not know the total viewport height in advance, and the scrolling speed differs depending on which rows are currently visible.

Example: How to Implement Custom Scroll Animation for Per-Pixel Scrolling

This example shows how to handle the CustomScrollAnimation event to implement custom animation played when grid data is vertically scrolled (per-pixel scrolling). Note the view's AllowPerPixelScrolling and AllowScrollAnimation options must be enabled.

View Example

MainWindow.xaml.vb

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Documents
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Imports System.Windows.Navigation
Imports System.Windows.Shapes
Imports System.Windows.Media.Animation

Namespace DXGrid_CustomScrollAnimation
    ''' <summary>
    ''' Interaction logic for MainWindow.xaml
    ''' </summary>
    Partial Public Class MainWindow
        Inherits Window

        Public Sub New()
            InitializeComponent()
            grid.ItemsSource = GetData()
        End Sub

        Private Sub tableView1_CustomScrollAnimation(ByVal sender As Object, ByVal e As DevExpress.Xpf.Grid.CustomScrollAnimationEventArgs)
            e.Storyboard = New Storyboard()
            Dim animation As New DoubleAnimation()
            animation.From = e.OldOffset
            animation.To = e.NewOffset
            animation.Duration = New Duration(TimeSpan.FromMilliseconds(600))
            animation.EasingFunction = New ExponentialEase() With {.Exponent = 0}
            e.Storyboard.Children.Add(animation)
        End Sub

        Private Function GetData() As List(Of TestDataObject)
            Dim _list As New List(Of TestDataObject)()
            For i As Integer = 0 To 99
                _list.Add(New TestDataObject() With {.ID = i, .Value = String.Format("Value {0}", i)})
            Next i
            Return _list
        End Function
    End Class

    Public Class TestDataObject
        Public Property ID() As Integer
        Public Property Value() As String
    End Class
End Namespace

Application.xaml

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

    </Application.Resources>
</Application>

Products.vb

Imports System.Collections.Generic
Imports System.Collections.ObjectModel

Public Class Product
    Public Property ProductName() As String
    Public Property Country() As String
    Public Property City() As String
    Public Property UnitPrice() As Double
    Public Property Quantity() As Integer
End Class

Public Class ProductList
    Inherits ObservableCollection(Of Product)

    Public Sub New()
        MyBase.New()
        Add(New Product() With {.ProductName = "Chang", .Country = "UK", .City = "Cowes", .UnitPrice = 19, .Quantity = 10})
        Add(New Product() With {.ProductName = "Gravad lax", .Country = "Italy", .City = "Reggio Emilia", .UnitPrice = 12.5, .Quantity = 16})
        Add(New Product() With {.ProductName = "Ravioli Angelo", .Country = "Brazil", .City = "Rio de Janeiro", .UnitPrice = 19, .Quantity = 12})
        Add(New Product() With {.ProductName = "Tarte au sucre", .Country = "Germany", .City = "QUICK-Stop", .UnitPrice = 22, .Quantity = 50})
        Add(New Product() With {.ProductName = "Steeleye Stout", .Country = "USA", .City = "Reggio Emilia", .UnitPrice = 18, .Quantity = 20})
        Add(New Product() With {.ProductName = "Pavlova", .Country = "Austria", .City = "Graz", .UnitPrice = 21, .Quantity = 52})
        Add(New Product() With {.ProductName = "Longlife Tofu", .Country = "USA", .City = "Boise", .UnitPrice = 7.75, .Quantity = 120})
        Add(New Product() With {.ProductName = "Alice Mutton", .Country = "Mexico", .City = "México D.F.", .UnitPrice = 21, .Quantity = 15})
        Add(New Product() With {.ProductName = "Alice Mutton", .Country = "Canada", .City = "Tsawwassen", .UnitPrice = 44, .Quantity = 16})
    End Sub
End Class

MainWindow.xaml

<Window x:Class="DXGrid_CustomScrollAnimation.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid">
    <Grid>
        <dxg:GridControl Name="grid" AutoPopulateColumns="True">
            <dxg:GridControl.View>
                <dxg:TableView Name="tableView1" AutoWidth="True"
                               AllowPerPixelScrolling="True"
                               ScrollAnimationMode="Custom"
                               CustomScrollAnimation="tableView1_CustomScrollAnimation"
                               AllowScrollAnimation="True"
                               />
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>

Application.xaml.vb

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

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

    End Class
End Namespace

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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 System.Windows.Media.Animation;

namespace DXGrid_CustomScrollAnimation {
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
            grid.ItemsSource = GetData();
        }

        private void tableView1_CustomScrollAnimation(object sender, DevExpress.Xpf.Grid.CustomScrollAnimationEventArgs e) {
            e.Storyboard = new Storyboard();
            DoubleAnimation animation = new DoubleAnimation();
            animation.From = e.OldOffset;
            animation.To = e.NewOffset;
            animation.Duration = new Duration(TimeSpan.FromMilliseconds(600));
            animation.EasingFunction = new ExponentialEase() { Exponent = 0 };
            e.Storyboard.Children.Add(animation);
        }

        private List<TestDataObject> GetData() {
            List<TestDataObject> _list = new List<TestDataObject>();
            for (int i = 0; i < 100; i++)
                _list.Add(new TestDataObject() { ID = i, Value = string.Format("Value {0}", i)  });
            return _list;
        }
    }

    public class TestDataObject {
        public int ID { get; set; }
        public string Value { get; set; }
    }
}

Products.cs

using System.Collections.Generic;
using System.Collections.ObjectModel;

public class Product {
    public string ProductName { get; set; }
    public string Country { get; set; }
    public string City { get; set; }
    public double UnitPrice { get; set; }
    public int Quantity { get; set; }
}

public class ProductList : ObservableCollection<Product> {
    public ProductList()
        : base() {
        Add(new Product() { ProductName = "Chang", Country = "UK", City = "Cowes", UnitPrice = 19, Quantity = 10 });
        Add(new Product() { ProductName = "Gravad lax", Country = "Italy", City = "Reggio Emilia", UnitPrice = 12.5, Quantity = 16 });
        Add(new Product() { ProductName = "Ravioli Angelo", Country = "Brazil", City = "Rio de Janeiro", UnitPrice = 19, Quantity = 12 });
        Add(new Product() { ProductName = "Tarte au sucre", Country = "Germany", City = "QUICK-Stop", UnitPrice = 22, Quantity = 50 });
        Add(new Product() { ProductName = "Steeleye Stout", Country = "USA", City = "Reggio Emilia", UnitPrice = 18, Quantity = 20 });
        Add(new Product() { ProductName = "Pavlova", Country = "Austria", City = "Graz", UnitPrice = 21, Quantity = 52 });
        Add(new Product() { ProductName = "Longlife Tofu", Country = "USA", City = "Boise", UnitPrice = 7.75, Quantity = 120 });
        Add(new Product() { ProductName = "Alice Mutton", Country = "Mexico", City = "México D.F.", UnitPrice = 21, Quantity = 15 });
        Add(new Product() { ProductName = "Alice Mutton", Country = "Canada", City = "Tsawwassen", UnitPrice = 44, Quantity = 16 });
    }
}