Rich Text Editor for WinForms - How to Enable Line Numbering and Count Document Rows

This example enables line numbering for the first document section. Line numbering starts at number one and restarts at the new section. Numbers are displayed on each second line and are indented from the text at a distance equal to 75 documents (0.25 of an inch).

The Custom Draw technique is used to display the line number column with a color background.

Implementation Details

The Section.LineNumbering property enables line numbering for the first document section.

Set the AllowDisplayLineNumbers property to true in the SimpleView and DraftView views to display line numbering. To make line numbers visible, the left padding is increased to 60 points.

The Line Number document style defines the used font and color.

Create a custom PagePainter descendant which implements the methods required to draw the column background and the line numbers. Handle the RichEditControl.BeforePagePaint event and set the BeforePagePaintEventArgs.Painter property to the PagePainter descendant instance.

Create an instance of the LayoutVisitor descendant and let it traverse the page layout. When it encounters a new row, it calls the VisitRow method. This method increments the row counter to count the lines on a page. To run the visitor each time after building the document layout, handle the DocumentLayout.DocumentFormatted event.

Files to Review

Form1.cs (VB: Form1.vb)
MyLayoutVisitor.cs (VB: MyLayoutVisitor.vb)
MyPagePainter.cs (VB: MyPagePainter.vb)

Documentation

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Example Code

LineNumberingExample/Form1.cs(vb)

C#
VB.NET

C#
//using DevExpress.XtraRichEdit.API.Layout;
//using DevExpress.XtraRichEdit.API.Native;
using DevExpress.Portable;
using DevExpress.XtraRichEdit;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace LineNumberingExample {
    public partial class Form1 : Form {

        public Form1() {
            InitializeComponent();
            ribbonControl1.SelectedPage = exampleRibbonPage1;

            richEditControl1.DocumentLoaded += RichEditControl1_DocumentLoaded;
            richEditControl1.DocumentLayout.DocumentFormatted += DocumentLayout_DocumentFormatted;
        }

        private void Form1_Load(object sender, EventArgs e) {
            richEditControl1.LoadDocument("Grimm.docx");
        }

        private void RichEditControl1_DocumentLoaded(object sender, EventArgs e) {
            richEditControl1.ActiveViewType = DevExpress.XtraRichEdit.RichEditViewType.Simple;
            #region #linenumbering
            this.richEditControl1.Views.SimpleView.Padding = new PortablePadding(60, 4, 4, 0);
            this.richEditControl1.Views.DraftView.Padding = new PortablePadding(60, 4, 4, 0);
            richEditControl1.Views.SimpleView.AllowDisplayLineNumbers = true;
            richEditControl1.Views.DraftView.AllowDisplayLineNumbers = true;

            richEditControl1.Document.Sections[0].LineNumbering.Start = 1;
            richEditControl1.Document.Sections[0].LineNumbering.CountBy = 2;
            richEditControl1.Document.Sections[0].LineNumbering.Distance = 75f;
           richEditControl1.Document.Sections[0].LineNumbering.RestartType = DevExpress.XtraRichEdit.API.Native.LineNumberingRestart.Continuous;

            richEditControl1.Document.CharacterStyles["Line Number"].FontName = "Courier";
            richEditControl1.Document.CharacterStyles["Line Number"].FontSize = 10;
            richEditControl1.Document.CharacterStyles["Line Number"].ForeColor = Color.DarkGray;
            richEditControl1.Document.CharacterStyles["Line Number"].Bold = true;
            #endregion #linenumbering
        }

        #region #BeforePagePaint
        private void RichEditControl1_BeforePagePaint(object sender, DevExpress.XtraRichEdit.BeforePagePaintEventArgs e) {
            if (e.CanvasOwnerType == DevExpress.XtraRichEdit.API.Layout.CanvasOwnerType.Printer) {
                return;
            }
            DevExpress.XtraRichEdit.API.Native.CharacterStyle style = richEditControl1.Document.CharacterStyles["Line Number"];
            MyPagePainter customPagePainter = new MyPagePainter(richEditControl1, SystemColors.Info, style);
            customPagePainter.LineNumberPadding = 60;
            e.Painter = customPagePainter;
        }
        #endregion #BeforePagePaint

        private void barCheckLineNumberBackColoring_CheckedChanged(object sender, DevExpress.XtraBars.ItemClickEventArgs e) {
            if (barCheckLineNumberBackColoring.Checked)
                richEditControl1.BeforePagePaint += RichEditControl1_BeforePagePaint;
            else
                richEditControl1.BeforePagePaint -= RichEditControl1_BeforePagePaint;
            richEditControl1.Refresh();
        }
        
        #region #DocumentFormatted
        private void DocumentLayout_DocumentFormatted(object sender, EventArgs e) {
            this.BeginInvoke((MethodInvoker)(() =>
            {
                if (this.Visible) {
                    MyLayoutVisitor visitor = new MyLayoutVisitor(richEditControl1.Document);
                    int pageCount = richEditControl1.DocumentLayout.GetFormattedPageCount();

                    for (int i = 0; i < pageCount; i++) {
                        visitor.Visit(richEditControl1.DocumentLayout.GetPage(i));
                    }
                    resultBarStaticItem.Caption = String.Format("Document has {0} lines", visitor.RowIndex);
                }
            }));
        }
        #endregion #DocumentFormatted

    }
}

Visual Basic
'using DevExpress.XtraRichEdit.API.Layout;
'using DevExpress.XtraRichEdit.API.Native;
Imports DevExpress.Portable
Imports DevExpress.XtraRichEdit
Imports System
Imports System.ComponentModel
Imports System.Drawing
Imports System.Windows.Forms

Namespace LineNumberingExample

    Public Partial Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent()
            ribbonControl1.SelectedPage = exampleRibbonPage1
            AddHandler richEditControl1.DocumentLoaded, AddressOf RichEditControl1_DocumentLoaded
            AddHandler richEditControl1.DocumentLayout.DocumentFormatted, AddressOf Me.DocumentLayout_DocumentFormatted
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
            richEditControl1.LoadDocument("Grimm.docx")
        End Sub

        Private Sub RichEditControl1_DocumentLoaded(ByVal sender As Object, ByVal e As EventArgs)
            richEditControl1.ActiveViewType = RichEditViewType.Simple
#Region "#linenumbering"
            richEditControl1.Views.SimpleView.Padding = New PortablePadding(60, 4, 4, 0)
            richEditControl1.Views.DraftView.Padding = New PortablePadding(60, 4, 4, 0)
            richEditControl1.Views.SimpleView.AllowDisplayLineNumbers = True
            richEditControl1.Views.DraftView.AllowDisplayLineNumbers = True
            richEditControl1.Document.Sections(0).LineNumbering.Start = 1
            richEditControl1.Document.Sections(0).LineNumbering.CountBy = 2
            richEditControl1.Document.Sections(0).LineNumbering.Distance = 75F
            richEditControl1.Document.Sections(0).LineNumbering.RestartType = API.Native.LineNumberingRestart.Continuous
            richEditControl1.Document.CharacterStyles("Line Number").FontName = "Courier"
            richEditControl1.Document.CharacterStyles("Line Number").FontSize = 10
            richEditControl1.Document.CharacterStyles("Line Number").ForeColor = Color.DarkGray
            richEditControl1.Document.CharacterStyles("Line Number").Bold = True
#End Region  ' #linenumbering
        End Sub

#Region "#BeforePagePaint"
        Private Sub RichEditControl1_BeforePagePaint(ByVal sender As Object, ByVal e As BeforePagePaintEventArgs)
            If e.CanvasOwnerType = API.Layout.CanvasOwnerType.Printer Then
                Return
            End If

            Dim style As API.Native.CharacterStyle = richEditControl1.Document.CharacterStyles("Line Number")
            Dim customPagePainter As MyPagePainter = New MyPagePainter(richEditControl1, SystemColors.Info, style)
            customPagePainter.LineNumberPadding = 60
            e.Painter = customPagePainter
        End Sub

#End Region  ' #BeforePagePaint
        Private Sub barCheckLineNumberBackColoring_CheckedChanged(ByVal sender As Object, ByVal e As DevExpress.XtraBars.ItemClickEventArgs)
            If barCheckLineNumberBackColoring.Checked Then
                AddHandler richEditControl1.BeforePagePaint, AddressOf RichEditControl1_BeforePagePaint
            Else
                RemoveHandler richEditControl1.BeforePagePaint, AddressOf RichEditControl1_BeforePagePaint
            End If

            richEditControl1.Refresh()
        End Sub

#Region "#DocumentFormatted"
        Private Sub DocumentLayout_DocumentFormatted(ByVal sender As Object, ByVal e As EventArgs)
            BeginInvoke(CType((Sub()
                If Visible Then
                    Dim visitor As MyLayoutVisitor = New MyLayoutVisitor(richEditControl1.Document)
                    Dim pageCount As Integer = richEditControl1.DocumentLayout.GetFormattedPageCount()
                    For i As Integer = 0 To pageCount - 1
                        visitor.Visit(richEditControl1.DocumentLayout.GetPage(i))
                    Next

                    resultBarStaticItem.Caption = String.Format("Document has {0} lines", visitor.RowIndex)
                End If
            End Sub), MethodInvoker))
        End Sub
#End Region  ' #DocumentFormatted
    End Class
End Namespace

LineNumberingExample/MyLayoutVisitor.cs(vb)

C#
VB.NET

C#
using DevExpress.XtraRichEdit.API.Layout;
using DevExpress.XtraRichEdit.API.Native;
using System;

namespace LineNumberingExample {
    #region #MyLayoutVisitor
    public class MyLayoutVisitor : LayoutVisitor {
        Document document;

        public int RowIndex { get; private set; }

        public MyLayoutVisitor(Document doc) {
            this.document = doc;
            RowIndex = 0;
        }

        protected override void VisitRow(LayoutRow row) {
            RowIndex++;
            base.VisitRow(row);
        }
    }
    #endregion #MyLayoutVisitor
}

Visual Basic
Imports DevExpress.XtraRichEdit.API.Layout
Imports DevExpress.XtraRichEdit.API.Native

Namespace LineNumberingExample

#Region "#MyLayoutVisitor"
    Public Class MyLayoutVisitor
        Inherits LayoutVisitor

        Private _RowIndex As Integer

        Private document As Document

        Public Property RowIndex As Integer
            Get
                Return _RowIndex
            End Get

            Private Set(ByVal value As Integer)
                _RowIndex = value
            End Set
        End Property

        Public Sub New(ByVal doc As Document)
            document = doc
            RowIndex = 0
        End Sub

        Protected Overrides Sub VisitRow(ByVal row As LayoutRow)
            RowIndex += 1
            MyBase.VisitRow(row)
        End Sub
    End Class
#End Region  ' #MyLayoutVisitor
End Namespace

LineNumberingExample/MyPagePainter.cs(vb)

C#
VB.NET

C#
using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Layout;
using DevExpress.XtraRichEdit.API.Native;
using System.Drawing;

namespace LineNumberingExample {
    #region #MyPagePainter
    public class MyPagePainter : PagePainter {
        RichEditControl richEditControl;
        int previousColumnIndex = -1;
        Font lineNumberFont;

        public MyPagePainter(RichEditControl richEdit)
            : base() {
            richEditControl = richEdit;
        }

        public MyPagePainter(RichEditControl richEdit, Color backColor, CharacterStyle style) 
            : base() {
            richEditControl = richEdit;
            NumberingHighlightColor = backColor;
            NumberingFontName = style.FontName;
            NumberingFontSize = style.FontSize ?? 10F;
            NumberingFontColor = style.ForeColor ?? Color.Black;
        }

        public string NumberingFontName { get; set; }
        public float NumberingFontSize { get; set; }
        public Color NumberingFontColor { get; set; }
        public Color NumberingHighlightColor { get; set; }
        public int LineNumberPadding { get; set; }

        public override void DrawPage(LayoutPage page) {
            lineNumberFont = new Font(NumberingFontName, NumberingFontSize, FontStyle.Regular);
            base.DrawPage(page);
            lineNumberFont.Dispose();
        }
 
        public override void DrawPageArea(LayoutPageArea pageArea) {
            Rectangle lineNumberBounds = new Rectangle(new Point(-LineNumberPadding, 0), new Size(LineNumberPadding, pageArea.Bounds.Height));
            Canvas.FillRectangle(new RichEditBrush(NumberingHighlightColor), lineNumberBounds);
            base.DrawPageArea(pageArea);
            previousColumnIndex = -1;
        }
        public override void DrawColumn(LayoutColumn column) {
            LayoutPageArea pageArea = column.GetParentByType<LayoutPageArea>();
            if (pageArea != null) {
                int leftBoundary = 0;
                if (previousColumnIndex >= 0) {
                    leftBoundary = pageArea.Columns[previousColumnIndex].Bounds.Right;
                }
                if (column.LineNumbers.Count > 0) {
                    HighlightLineNumberingArea(column, leftBoundary);
                }
                previousColumnIndex++;
            }
            base.DrawColumn(column);
        }

        public override void DrawLineNumberBox(LineNumberBox lineNumberBox) {
            Canvas.DrawString(lineNumberBox.Text, lineNumberFont, new RichEditBrush(NumberingFontColor), lineNumberBox.Bounds, this.richEditControl.LayoutUnit);
        }

        void HighlightLineNumberingArea(LayoutColumn column, int leftBoundary) {
                LayoutPage page = column.GetParentByType<LayoutPage>();
            Rectangle marginBounds = new Rectangle(new Point(leftBoundary, 0), new Size(column.Bounds.X - leftBoundary, page.Bounds.Height));
            Canvas.FillRectangle(new RichEditBrush(NumberingHighlightColor), marginBounds);
        }
    }
    #endregion #MyPagePainter
}

Visual Basic
Imports DevExpress.XtraRichEdit
Imports DevExpress.XtraRichEdit.API.Layout
Imports DevExpress.XtraRichEdit.API.Native
Imports System.Drawing

Namespace LineNumberingExample

#Region "#MyPagePainter"
    Public Class MyPagePainter
        Inherits PagePainter

        Private richEditControl As RichEditControl

        Private previousColumnIndex As Integer = -1

        Private lineNumberFont As Font

        Public Sub New(ByVal richEdit As RichEditControl)
            MyBase.New()
            richEditControl = richEdit
        End Sub

        Public Sub New(ByVal richEdit As RichEditControl, ByVal backColor As Color, ByVal style As CharacterStyle)
            MyBase.New()
            richEditControl = richEdit
            NumberingHighlightColor = backColor
            NumberingFontName = style.FontName
            NumberingFontSize = If(style.FontSize, 10F)
            NumberingFontColor = If(style.ForeColor, Color.Black)
        End Sub

        Public Property NumberingFontName As String

        Public Property NumberingFontSize As Single

        Public Property NumberingFontColor As Color

        Public Property NumberingHighlightColor As Color

        Public Property LineNumberPadding As Integer

        Public Overrides Sub DrawPage(ByVal page As LayoutPage)
            lineNumberFont = New Font(NumberingFontName, NumberingFontSize, FontStyle.Regular)
            MyBase.DrawPage(page)
            lineNumberFont.Dispose()
        End Sub

        Public Overrides Sub DrawPageArea(ByVal pageArea As LayoutPageArea)
            Dim lineNumberBounds As Rectangle = New Rectangle(New Point(-LineNumberPadding, 0), New Size(LineNumberPadding, pageArea.Bounds.Height))
            Canvas.FillRectangle(New RichEditBrush(NumberingHighlightColor), lineNumberBounds)
            MyBase.DrawPageArea(pageArea)
            previousColumnIndex = -1
        End Sub

        Public Overrides Sub DrawColumn(ByVal column As LayoutColumn)
            Dim pageArea As LayoutPageArea = column.GetParentByType(Of LayoutPageArea)()
            If pageArea IsNot Nothing Then
                Dim leftBoundary As Integer = 0
                If previousColumnIndex >= 0 Then
                    leftBoundary = pageArea.Columns(previousColumnIndex).Bounds.Right
                End If

                If column.LineNumbers.Count > 0 Then
                    HighlightLineNumberingArea(column, leftBoundary)
                End If

                previousColumnIndex += 1
            End If

            MyBase.DrawColumn(column)
        End Sub

        Public Overrides Sub DrawLineNumberBox(ByVal lineNumberBox As LineNumberBox)
            Canvas.DrawString(lineNumberBox.Text, lineNumberFont, New RichEditBrush(NumberingFontColor), lineNumberBox.Bounds, richEditControl.LayoutUnit)
        End Sub

        Private Sub HighlightLineNumberingArea(ByVal column As LayoutColumn, ByVal leftBoundary As Integer)
            Dim page As LayoutPage = column.GetParentByType(Of LayoutPage)()
            Dim marginBounds As Rectangle = New Rectangle(New Point(leftBoundary, 0), New Size(column.Bounds.X - leftBoundary, page.Bounds.Height))
            Canvas.FillRectangle(New RichEditBrush(NumberingHighlightColor), marginBounds)
        End Sub
    End Class
#End Region  ' #MyPagePainter
End Namespace

DevExpress Support Team

last modified a year ago

Modified: October 23, 2023 3:44 PM

Platform: WinForms

Product: XtraRichEdit

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