WPF Data Grid - Use a RichTextBox to Display and Edit Grid Data

C#
using System.IO;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;

namespace GridApplication {
    public class RichTextBoxEx : RichTextBox {
        bool IsSettingText;

        public static readonly DependencyProperty RtfTextProperty =
            DependencyProperty.Register("RtfText", typeof(string), typeof(RichTextBoxEx),
            new FrameworkPropertyMetadata(string.Empty,
            FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnRtfTextChanged));

        static void OnRtfTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
            ((RichTextBoxEx)d).LoadText();
        }

        public string RtfText {
            get { return GetValue(RtfTextProperty) as string; }
            set { SetValue(RtfTextProperty, value); }
        }

        protected override void OnTextChanged(TextChangedEventArgs e) {
            Binding binding = BindingOperations.GetBinding(this, RtfTextProperty);
            if (binding != null && binding.Mode != BindingMode.OneWay) {
                SaveText();
            }
            base.OnTextChanged(e);
        }

        void LoadText() {
            if (IsSettingText)
                return;

            string rtfText = RtfText;
            Document.Blocks.Clear();

            if (!string.IsNullOrEmpty(rtfText)) {
                TextRange tr = new TextRange(Document.ContentStart, Document.ContentEnd);

                using (MemoryStream rtfMemoryStream =
                new MemoryStream(Encoding.ASCII.GetBytes(rtfText))) {

                    tr.Load(rtfMemoryStream, DataFormats.Rtf);
                }
            }
        }

        void SaveText() {
            TextRange tr = new TextRange(Document.ContentStart, Document.ContentEnd);

            string CurrentText = tr.Text;

            using (MemoryStream ms = new MemoryStream(CurrentText.Length * 2)) {
                tr.Save(ms, DataFormats.Rtf);
                string rtfText = ASCIIEncoding.Default.GetString(ms.ToArray());
                SetRtfText(rtfText);
            }
        }

        void SetRtfText(string value) {
            IsSettingText = true;
            try {
                RtfText = value;
            }
            finally {
                IsSettingText = false;
            }
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports System.IO
Imports System.Text
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Documents

Namespace GridApplication
    Public Class RichTextBoxEx
        Inherits RichTextBox
        Private IsSettingText As Boolean

        Public Shared ReadOnly RtfTextProperty As DependencyProperty = DependencyProperty.Register("RtfText", GetType(String), GetType(RichTextBoxEx), New FrameworkPropertyMetadata(String.Empty, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, AddressOf OnRtfTextChanged))

        Private Shared Sub OnRtfTextChanged(ByVal d As DependencyObject, ByVal e As DependencyPropertyChangedEventArgs)
            CType(d, RichTextBoxEx).LoadText()
        End Sub

        Public Property RtfText() As String
            Get
                Return TryCast(GetValue(RtfTextProperty), String)
            End Get
            Set(ByVal value As String)
                SetValue(RtfTextProperty, value)
            End Set
        End Property

        Protected Overrides Sub OnTextChanged(ByVal e As TextChangedEventArgs)
            Dim binding As Binding = BindingOperations.GetBinding(Me, RtfTextProperty)
            If binding IsNot Nothing AndAlso binding.Mode <> BindingMode.OneWay Then
                SaveText()
            End If
            MyBase.OnTextChanged(e)
        End Sub

        Private Sub LoadText()
            If IsSettingText Then
                Return
            End If

            Dim rtfText As String = Me.RtfText
            Document.Blocks.Clear()

            If (Not String.IsNullOrEmpty(rtfText)) Then
                Dim tr As New TextRange(Document.ContentStart, Document.ContentEnd)

                Using rtfMemoryStream As New MemoryStream(Encoding.ASCII.GetBytes(rtfText))

                    tr.Load(rtfMemoryStream, DataFormats.Rtf)
                End Using
            End If
        End Sub

        Private Sub SaveText()
            Dim tr As New TextRange(Document.ContentStart, Document.ContentEnd)

            Dim CurrentText As String = tr.Text

            Using ms As New MemoryStream(CurrentText.Length * 2)
                tr.Save(ms, DataFormats.Rtf)
                Dim rtfText As String = ASCIIEncoding.Default.GetString(ms.ToArray())
                SetRtfText(rtfText)
            End Using
        End Sub

        Private Sub SetRtfText(ByVal value As String)
            IsSettingText = True
            Try
                RtfText = value
            Finally
                IsSettingText = False
            End Try
        End Sub
    End Class
End Namespace

C#
using System.Data;
using System.Windows;
using System.Windows.Input;
using DevExpress.Xpf.Editors;

namespace GridApplication {

    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();
            DataSet dataSet = new DataSet();
            dataSet.ReadXml("Cars2.xml");
            grid.ItemsSource = dataSet.Tables[0];
        }

        private void view_GetActiveEditorNeedsKey(object sender, DevExpress.Xpf.Grid.GetActiveEditorNeedsKeyEventArgs e) {
            if(e.Column.FieldName == "RtfContent") {
                if(e.Key == Key.Enter && !e.Modifiers.HasFlag(ModifierKeys.Control))
                    e.NeedsKey = true;
            }
        }

        private void view_ProcessEditorActivationAction(object sender, DevExpress.Xpf.Grid.ProcessEditorActivationActionEventArgs e) {
            if(e.Column.FieldName == "RtfContent") {
                if(e.ActivationAction == ActivationAction.MouseLeftButtonDown)
                    e.RaiseEventAgain = true;
            }
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports System.Data
Imports System.Windows
Imports System.Windows.Input
Imports DevExpress.Xpf.Editors

Namespace GridApplication

    Partial Public Class Window1
        Inherits Window
        Public Sub New()
            InitializeComponent()
            Dim dataSet As New DataSet()
            dataSet.ReadXml("Cars2.xml")
            grid.ItemsSource = dataSet.Tables(0)
        End Sub
    End Class

    Public Class RichTextEdit
        Inherits TextEdit
        Protected Overrides Function NeedsKey(ByVal key As Key, ByVal modifiers As ModifierKeys) As Boolean
            If EditMode = EditMode.InplaceActive AndAlso key = Key.Enter AndAlso (modifiers And ModifierKeys.Control) = 0 Then
                Return True
            End If

            Return MyBase.NeedsKey(key, modifiers)
        End Function
    End Class
End Namespace