MainWindow.xaml

<dx:ThemedWindow
    x:Class="HowToEditCell.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
    xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors"
    xmlns:dxpg="http://schemas.devexpress.com/winfx/2008/xaml/pivotgrid"
    xmlns:local="clr-namespace:HowToEditCell"
    Width="800"
    Height="450"
    Loaded="Window_Loaded"
    Title="How to Edit Cell">

    <Grid>
        <dxpg:PivotGridControl
            x:Name="pivotGridControl1"
            DataProcessingEngine="Optimized"
            local:PivotGridEditHelper.OnCellEdit="pivotGridControl1_OnCellEdit"
            local:PivotGridEditHelper.UseHelper="{Binding RelativeSource={RelativeSource Self}}">
            <dxpg:PivotGridControl.Fields>
                <dxpg:PivotGridField
                    x:Name="fieldSales"
                    Area="DataArea"
                    Caption="Product Sales">
                    <dxpg:PivotGridField.DataBinding>
                        <dxpg:DataSourceColumnBinding ColumnName="ExtendedPrice"/>
                    </dxpg:PivotGridField.DataBinding>
                    <dxpg:PivotGridField.CellTemplate>
                        <DataTemplate>
                            <dxe:TextEdit
                                x:Name="edit"
                                HorizontalContentAlignment="Right"
                                DisplayFormatString="c2"
                                EditMode="InplaceInactive"
                                EditValue="{Binding Value, Mode=OneWay}"
                                local:PivotGridEditHelper.LostFocusCommand="{x:Static local:PivotGridEditHelper.Enter}"
                                Mask="[0-9]*\.[0-9]{0,2}"
                                MaskType="RegEx">
                                <dxe:TextEdit.InputBindings>
                                    <KeyBinding
                                        Key="Enter"
                                        Command="{x:Static local:PivotGridEditHelper.Enter}"
                                        CommandParameter="{Binding ElementName=edit}" />
                                    <MouseBinding
                                        Command="{x:Static local:PivotGridEditHelper.StartEdit}"
                                        CommandParameter="{Binding ElementName=edit}"
                                        MouseAction="LeftClick" />
                                </dxe:TextEdit.InputBindings>
                            </dxe:TextEdit>
                        </DataTemplate>
                    </dxpg:PivotGridField.CellTemplate>
                </dxpg:PivotGridField>
                <dxpg:PivotGridField
                    x:Name="fieldYear"
                    AllowFilter="False"
                    Area="ColumnArea"
                    Caption="Year">
                    <dxpg:PivotGridField.DataBinding>
                        <dxpg:DataSourceColumnBinding ColumnName="OrderDate" GroupInterval="DateYear"/>
                    </dxpg:PivotGridField.DataBinding>

                </dxpg:PivotGridField>
                <dxpg:PivotGridField
                    x:Name="fieldCategoryName"
                    Area="RowArea"
                    AreaIndex="0"
                    Caption="Category">
                    <dxpg:PivotGridField.DataBinding>
                        <dxpg:DataSourceColumnBinding ColumnName="CategoryName"/>
                    </dxpg:PivotGridField.DataBinding>
                </dxpg:PivotGridField>
                <dxpg:PivotGridField
                    x:Name="fieldProductName"
                    Area="RowArea"
                    AreaIndex="1"
                    Caption="Product">
                    <dxpg:PivotGridField.DataBinding>
                        <dxpg:DataSourceColumnBinding ColumnName="ProductName"/>
                    </dxpg:PivotGridField.DataBinding>
                </dxpg:PivotGridField>
                <dxpg:PivotGridField
                    Area="DataArea"
                    Caption="Percent Of Column"
                    CellFormat="p"
                    Name="fieldExtendedPrice2">
                    <dxpg:PivotGridField.DataBinding>
                        <dxpg:PercentOfTotalBinding PartitioningCriteria="ColumnValue">
                            <dxpg:PercentOfTotalBinding.Source>
                                <dxpg:DataSourceColumnBinding ColumnName="ExtendedPrice"/>
                            </dxpg:PercentOfTotalBinding.Source>
                        </dxpg:PercentOfTotalBinding>
                    </dxpg:PivotGridField.DataBinding>
                </dxpg:PivotGridField>
            </dxpg:PivotGridControl.Fields>
        </dxpg:PivotGridControl>
    </Grid>

</dx:ThemedWindow>