Checkbox is not checked in DevExpress GridControl using wpf

I am trying to work on DevExpress GridControl Checkbox column but problem is that when I binding the checkbox value in XAML code dynamically its not work perfectlly below I provide you my demo project code :-

XAML Code:-

<dxg:GridControl AutoPopulateColumns="True" HorizontalAlignment="Left"  Margin="0,40,0,0" Name="gridControl1" VerticalAlignment="Top" Height="318" Width="503">
            <dxg:GridControl.View>
                <dxg:TableView Name="tableView1" ShowTotalSummary="True" />
            </dxg:GridControl.View>
            <dxg:GridControl.Columns>
                <dxg:GridColumn DisplayMemberBinding="{Binding Path=EvenOdd}" Header="Even/Odd" />
                <dxg:GridColumn Name="PickColumn" Header="Pick" Width="30" 
                                    AllowColumnFiltering="False" AllowSorting="False">
                    <dxg:GridColumn.CellTemplate>
                        <DataTemplate>
                            <CheckBox IsChecked="{Binding Path=IsValid}"
                                          HorizontalAlignment="Center" VerticalAlignment="Center" >
                            </CheckBox>
                        </DataTemplate>
                    </dxg:GridColumn.CellTemplate>
                </dxg:GridColumn>
            </dxg:GridControl.Columns>
        </dxg:GridControl>

my cs file code:-

public class ss
{
  public bool IsValid { get; set; }
  public string EvenOdd { get; set; }
}

Code Behind:

    public List<ss> sList = new List<ss>();


    private void Window_Loaded(object sender, RoutedEventArgs e)
    {

        for (int i = 0; i < 10; i++)
        {

            if (i % 2 == 0)
            {
                sList.Add(new ss { IsValid = true, EvenOdd = "Even" });
            }
            else
            {
                sList.Add(new ss { IsValid = false, EvenOdd = "Odd" });
            }
        }

       gridControl1.ItemsSource = sList;
    }

Solution

Adding on to HighCore's answer. If you would like to edit the data in your grid.

See ColumnBase.CellTemplate Property:

To enable data editing, use an editor shipped with the DevExpress Data Editors Library for WPF. The editor's Name must be set to 'PART_Editor'.

Standard controls can be used in CellTemplate only for display purposes. Data editing is not allowed.

Then,

xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors" 

<dxg:GridColumn Name="PickColumn" 
                Header="Pick" 
                Width="30" 
                AllowColumnFiltering="False" 
                AllowSorting="False">
    <dxg:GridColumn.CellTemplate>
        <DataTemplate>
            <dxe:CheckEdit x:Name="PART_Editor"
                           EditValue="{Binding Path=Data.IsValid, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
        </DataTemplate>
    </dxg:GridColumn.CellTemplate>
</dxg:GridColumn>

You still need to use HighCore's implementation of INotifyPropertyChanged.