Mouse Scrolling in DataGrid in Silverlight 3

Introduction

In this article we will see how can we scroll with mouse for a DataGrid.

Creating Silverlight Project

Fire up Visual Studio 2008 and create a new Silverlight 3 Project. Name it as MouseScroll.



Add a Class to the Silverlight Project and name it as ScrollDataGrid.cs

Now inherit DataGrid to the class as follows:

public class ScollDataGrid: DataGrid
{
}

You need to use the following namespaces in this class.

using System.Windows.Automation.Peers;
using System.Windows.Automation.Provider;
using System.Windows.Automation;

Now write a method for OnMouseWheel as described below:

protected override void OnMouseWheel(MouseWheelEventArgs e)
{
    base.OnMouseWheel(e);
    //Try getting the automationpeer from this datagrid
    AutomationPeer automationPeer = FrameworkElementAutomationPeer.FromElement(this);
    if (automationPeer == null)
    {
        //if not try creating a new one for this datagrid
        automationPeer = FrameworkElementAutomationPeer.CreatePeerForElement(this);
    }
    //Try getting the scroll provider for this datagrid
    IScrollProvider scrollProvider = automationPeer.GetPattern(PatternInterface.Scroll) as IScrollProvider;
    if (scrollProvider != null)
    {
        ScrollAmount scrollAmount = ScrollAmount.NoAmount;
        if (e.Delta < 0)
            scrollAmount = ScrollAmount.SmallIncrement;//for scroll down
        else if (e.Delta > 0)
            scrollAmount = ScrollAmount.SmallDecrement;//for scoll up 

        if (scrollProvider.VerticallyScrollable)
        {
            scrollProvider.Scroll(ScrollAmount.NoAmount, scrollAmount);
        }
    }
}

Now in the MainPage.xaml add the namespace as follows:

xmlns:local="clr-namespace:MouseScroll"

Now place a DataGrid of type ScrollDataGrid and use the normal properties of DataGrid to look better.

<local:ScollDataGrid x:Name="myDataGrid" Height="100" HorizontalAlignment="Left" VerticalAlignment="Top" Width="271" Margin="20,20,0,0" />

Now we will write some dummy data to fill in the DataGrid.

public class PersonalData
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
}

Create a list of the above class and bind data to DataGrid.

public partial class MainPage : UserControl
{
    List<PersonalData> myList;
    public MainPage()
    {
        InitializeComponent();
        #region Dummy List
        myList = new List<PersonalData> 
        {
            new PersonalData{ FirstName="FirstName1", LastName="LastName1", Age=39},
            new PersonalData{ FirstName="FirstName2", LastName="LastName2", Age=40},
            new PersonalData{ FirstName="FirstName3", LastName="LastName3", Age=41},
            new PersonalData{ FirstName="FirstName4", LastName="LastName4", Age=42},
            new PersonalData{ FirstName="FirstName5", LastName="LastName5", Age=43},
            new PersonalData{ FirstName="FirstName6", LastName="LastName6", Age=44},
            new PersonalData{ FirstName="FirstName7", LastName="LastName7", Age=45},
            new PersonalData{ FirstName="FirstName8", LastName="LastName8", Age=46},
            new PersonalData{ FirstName="FirstName9", LastName="LastName9", Age=47},
            new PersonalData{ FirstName="FirstName10", LastName="LastName10", Age=48},
            new PersonalData{ FirstName="FirstName11", LastName="LastName11", Age=49},
            new PersonalData{ FirstName="FirstName12", LastName="LastName12", Age=50},
            new PersonalData{ FirstName="FirstName13", LastName="LastName13", Age=51},
            new PersonalData{ FirstName="FirstName14", LastName="LastName14", Age=52},
        }; 
        #endregion
        myDataGrid.ItemsSource = myList;
    }
}

That's it now run your application and scroll the DataGrid with your mouse. 



Hope this helps.