public class AutoGrid : Grid
    {
        #region Execute Mapping Events

        protected override void OnInitialized(EventArgs e)
        {
            base.OnInitialized(e);
            RecomputeGridMapping();
        }

        protected override void OnVisualChildrenChanged(DependencyObject visualAdded, DependencyObject visualRemoved)
        {
            base.OnVisualChildrenChanged(visualAdded, visualRemoved);

            if (IsInitialized)
                RecomputeGridMappingOnce();
        }

        void Columns_Changed(DependencyPropertyChangedEventArgs e)
        {
            if (IsInitialized)
                RecomputeGridMappingOnce();
        }

        #endregion

        #region Mapping Core

        DispatcherOnceInvoker RecomputeGridMappingOnceInvoker = new DispatcherOnceInvoker();

        void RecomputeGridMappingOnce()
        {
            RecomputeGridMappingOnceInvoker.BeginInvokeOnce(RecomputeGridMapping);
        }

        void RecomputeGridMapping()
        {
            CreateRows();
            CreateColumns();
            MapChildren();
        }

        void CreateRows()
        {
            var rows = Children.Count / Columns;

            if (Children.Count % Columns > 0)
                rows++;

            while (RowDefinitions.Count > rows && RemoveLastAutoGeneratedItem(RowDefinitions))
            { }

            while (RowDefinitions.Count < rows)
            {
                var row = new RowDefinition { Height = GridLength.Auto };
                SetIsAutoGenerated(row, true);
                RowDefinitions.Add(row);
            }
        }

        void CreateColumns()
        {
            while (ColumnDefinitions.Count > Columns && RemoveLastAutoGeneratedItem(ColumnDefinitions))
            { }

            while (ColumnDefinitions.Count < Columns)
            {
                var column = new ColumnDefinition { Width = GridLength.Auto };
                SetIsAutoGenerated(column, true);
                ColumnDefinitions.Add(column);
            }

            if (ColumnDefinitions.Count > 0)
            {
                var lastColumn = ColumnDefinitions[ColumnDefinitions.Count - 1];
                if (GetIsAutoGenerated(lastColumn))
                    lastColumn.ClearValue(ColumnDefinition.WidthProperty);
            }
        }

        bool RemoveLastAutoGeneratedItem<T>(IList<T> list)
            where T : DependencyObject
        {
            var index = list.LastIndex(v => GetIsAutoGenerated(v));
            if (index >= 0)
            {
                list.RemoveAt(index);
                return true;
            }
            return false;
        }

        void MapChildren()
        {
            int i = 0;
            foreach (UIElement child in Children)
            {
                SetColumn(child, i % Columns);
                SetRow(child, i / Columns);
                i++;
            }
        }

        #endregion

        #region Columns Property

        public static readonly DependencyProperty ColumnsProperty =
            DependencyProperty.Register(
                "Columns",
                typeof(int),
                typeof(AutoGrid),
                new FrameworkPropertyMetadata(2, (s, e) => ((AutoGrid)s).Columns_Changed(e))
            );

        public int Columns
        {
            get { return (int)GetValue(ColumnsProperty); }
            set { SetValue(ColumnsProperty, value); }
        }

        #endregion

        #region IsAutoGenerated Property

        static readonly DependencyProperty IsAutoGeneratedProperty =
            DependencyProperty.RegisterAttached(
                "IsAutoGenerated",
                typeof(bool),
                typeof(AutoGrid)
            );

        static bool GetIsAutoGenerated(DependencyObject target)
        {
            return (bool)target.GetValue(IsAutoGeneratedProperty);
        }

        static void SetIsAutoGenerated(DependencyObject target, bool value)
        {
            target.SetValue(IsAutoGeneratedProperty, value);
        }

        #endregion
    }

    public class DispatcherOnceInvoker : DispatcherObject
    {
        Action Action;

        public void BeginInvokeOnce(Action action)
        {
            VerifyAccess();

            if (Action != null)
                return;

            Action = action;

            Dispatcher.BeginInvoke(() =>
            {
                var actionToExecute = GetActionAndReset();
                actionToExecute();
            });
        }

        Action GetActionAndReset()
        {
            var result = Action;
            Action = null;
            return result;
        }
    }

<UserControl x:Class="Personal.FrmPersonalEdit"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:s="clr-namespace:SspMain;assembly=SspMainWpf"
             xmlns:my="clr-namespace:Personal"
             mc:Ignorable="d" 
             Width="400">
    <s:AutoGrid DataContext="{Binding Data}">
        <TextBlock Margin="3" VerticalAlignment="Center" Text="Фамилия:"/>
        <TextBox Margin="3" HorizontalAlignment="Left" MinWidth="200">
            <TextBox.Text>
                <Binding Path="LastName" Converter="{my:CnvPersNamePart}">
                    <Binding.ValidationRules>
                        <s:NotNullRule/>
                        <my:PersNamePartRule/>
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>

        <TextBlock Margin="3" VerticalAlignment="Center" Text="Имя:"/>
        <TextBox Margin="3" HorizontalAlignment="Left" MinWidth="200">
            <TextBox.Text>
                <Binding Path="FirstName" Converter="{my:CnvPersNamePart}">
                    <Binding.ValidationRules>
                        <s:NotNullRule/>
                        <my:PersNamePartRule/>
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>

        <TextBlock Margin="3" VerticalAlignment="Center" Text="Отчество:"/>
        <TextBox Margin="3" HorizontalAlignment="Left" MinWidth="200">
            <Binding Path="PatrName" Converter="{my:CnvPersNamePart}">
                <Binding.ValidationRules>
                    <s:NotNullRule/>
                    <my:PersNamePartRule/>
                </Binding.ValidationRules>
            </Binding>
        </TextBox>

        <TextBlock Margin="3" VerticalAlignment="Center" Text="Табельный номер:"/>
        <TextBox Margin="3,3,0,3" MinWidth="80" HorizontalAlignment="Left">
            <TextBox.Text>
                <Binding Path="TabNum" Converter="{s:CnvInt}">
                    <Binding.ValidationRules>
                        <s:NotNullRule/>
                        <s:IntBetweenRule MinValue="1"/>
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>

        <TextBlock Text="Дата поступления:" VerticalAlignment="Center" Margin="3"/>
        <s:DateTimePicker Value="{Binding EntranceDate}" FormatMode="Date" Margin="3"/>

        <TextBlock Text="Дата увольнения:" VerticalAlignment="Center" Margin="3"/>
        <s:DateTimePicker Value="{Binding RetireDate}" FormatMode="Date" Margin="3"/>

        <TextBlock Text="Примечания:" VerticalAlignment="Top" Margin="3"/>
        <TextBox Margin="3" 
                 Text="{Binding Notes}" 
                 Style="{StaticResource NotesTextBoxStyle}"/>
    </s:AutoGrid>
</UserControl>

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:my="clr-namespace:WpfApplication1"
        Title="MainWindow" Height="350" Width="525">
    <Window.DataContext>
        <my:Class1/>
    </Window.DataContext>
    <FlowDocumentScrollViewer>
        <FlowDocument>
            <Table>
                <TableRowGroup>
                    <TableRow>
                        <TableCell>
                            <Paragraph>Value1:</Paragraph>
                        </TableCell>
                        <TableCell>
                            <Paragraph>
                                <TextBox Width="200" Text="{Binding Value1}"/>
                            </Paragraph>
                        </TableCell>
                    </TableRow>
                    <TableRow>
                        <TableCell>
                            <Paragraph>Value2:</Paragraph>
                        </TableCell>
                        <TableCell>
                            <Paragraph>
                                <TextBox Width="200" Text="{Binding Value2}"/>
                            </Paragraph>
                        </TableCell>
                    </TableRow>
                </TableRowGroup>
            </Table>
        </FlowDocument>
    </FlowDocumentScrollViewer>
</Window>