Word Processing with an Extended Rich Text Box Control in VB.NET

Introduction

This article describes an easy approach to building a simple word processor around an extended version of the Rich Text Box (RTB) control; Microsoft has made available an extended version of the RTB control that greatly eases the requirements for printing the control's text or RTF content.  This article and the sample application will use this extended version of the RTF control to demonstrate the following word processor related functions:

  • Opening Text, RTF, HTML, or other text files into a RTB control
  • Saving Text, RTF, HTML, or other text files from an RTB control
  • Implementation of the Page Setup dialog control
  • Implementation of the Print Preview dialog control
  • Implementation of the Print dialog control
  • Setting font properties on selected text or RTF within the RTB control
  • Searching for and highlighting text contained within the RTB control
  • Searching for and replacing text contained within the RTB control
  • Adding Indentation to sections of an RTB's content
  • Adding Bullets to sections of an RTB's content
  • Implementing Undo/Redo within an RTB
  • Implementing Select All, Cut, Copy, and Paste in an RTB control
  • Embedding Images into an RTB control
  • Setting page and font colors
  • Implementing Alignment options in an RTB control

Whilst this project will not lead you to drop MS Word, it is a decent little word processor and to that end, you may find a use for it.  I have always kept one of these on hand and have frequently tailored them to do things like provide a custom tool for viewing reports, error logs, and things of that nature when I wanted to integrate that feature into a product so that I could use it in lieu of doing something like shelling out a text file into Notepad.  Doing so allows me to control the appearance of the application, the caption in the title bar of the form, etc.

pic1.gif

Figure 1:  The Editor Application in Use

Getting Started:

In order to get started, unzip the attachment and load the solution into Visual Studio 2005.  Examine the solution explorer and note the files contained in the project:

pic2.gif

Figure 2:  The Solution Explorer Showing the Project Files

First note that there are two separate projects contained in the solution.  The first project is a class library entitled, "ExtendedRichTextBox", that library contains a single control class, "RichTextBoxPrintCtrl.vb".  This control class was provided by Microsoft as an alternative to the basic Rich Text Box control; the class inherits from the RichTextBox control class but adds to that base class additional support for printing the control's content.  The approach provided by the control is far simpler than the traditional approach used as based upon the manipulation of the graphic context of the control.

The second solution is the editor application itself (RichTextEditor).  This application uses the extended rich text box control and then to that adds in all of the normal document manipulation techniques (such as font selection, indentation, and file IO support).  Aside from the main application's form (frmMain.vb), this project also includes two additional forms, one to search for a string within the RTB's content, and one to search for and replace strings within the RTB.  These forms are frmFind.vb and frmReplace.vb.

pic3.gif

Figure 3:  Editor Application Find Dialog

pic4.gif

Figure 4: Editor Application Find and Replace Dialog

In addition to the form classes mentioned, the solution also contains a folder entitled, "Graphics"; this folder contains all of the image files used to support the application's menus and toolbar.

Project References.

Aside from the default references, there are a couple of additional references added.  Most notably, the extended rich text box control library is added to allow for the use of the extended rich text box control.  Figure 2 shows the references as they exist in the project.

WordProcessing5.gif

Figure 5:  Project References

The Code:  Main Form Class.

The main form class (frmMain.vb) is pretty easy to follow.  It begins with a couple of import statements followed by the class declaration.  The code is divided by purpose into four separate regions which are:

  • Declarations
  • Menu Methods
  • Toolbar Methods
  • Printing

The imports and class declaration sections of code looks like this:

Imports System.Drawing

Imports System.Drawing.Image

 

Public Class frmMain

The class declaration is plain enough and does not inherit from or implement any base class or interface.  I would emphasis here again that making use of Microsoft's extended rich text box control greater reduces the amount of code necessary to support all of the methods used within this application.

The declarations section is also very simple; the section contains both of the variables used throughout the application.  The content is as follows:

#Region "Declarations"

 

    Private currentFile As String

    Private checkPrint As Integer

 

#End Region

The "currentFile" variable is used to keep track of the path and file name of the file loaded into the extended rich text box control; it is updated whenever the user opens a file, creates and saves a file, or saves a file with a new name and/or file extension.

The "checkPrint" variable is used by the streamlined printing process recommended by Microsoft in the article describing the use of the extended rich text box control.  It is used to determine if additional pages exist when the document is sent to the printer (in support of multi-page printing).

The next section of code is the primary block of code used by this application, the "Menu Methods" region contains all of the subroutines evoked in response to the selection of a menu option.  The "Toolbar Methods" region follows the "Menu Methods" region, but all of the subroutines in the toolbar control section call the subroutines defined in the "Menu Methods" region of the code unless the code was so trivial (one line) that it was just as simple to make the call directly as it was to call menu related subroutine; for that reason, this document will not describe the content of the "Toolbar Methods" region specifically.

The first block of code in the menu region is used to create a new file:

Private Sub NewToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles NewToolStripMenuItem.Click

 

    If rtbDoc.Modified Then

        Dim answer As Integer

        answer = MessageBox.Show("The current document has not been

saved, would you like to continue without saving?", "Unsaved

Document", MessageBoxButtons.YesNo, MessageBoxIcon.Question)

 

        If answer = Windows.Forms.DialogResult.Yes Then

            rtbDoc.Clear()

        Else

            Exit Sub

        End If

    Else

        rtbDoc.Clear()

    End If

 

    currentFile = ""

    Me.Text = "Editor: New Document"

End Sub 

In this subroutine, prior to clearing the current document, the status of the current document is checked by means using the controls "Modified" test; if the document has been modified while it has been open, the test will return true.  If the document has been modified, the user is queried with a message box to determine whether or not they want to save (or loose) the modifications made to the current file prior to clearing the file.  If they choose to save the changes, the subroutine is exited; else, the document is cleared, and the changes are lost.  If the document has not been modified, the subroutine will clear the document without notifying the user.  Whenever the document is cleared, the title of the control is updated to indicate that a new (unsaved) document is the current document, and the "currentFile" variable is set to contain an empty string.

WordProcessing6.gif

Figure 6:  Confirmation Dialog show after user requests new document with saving changes.

The next subroutine is used to open an existing file into the rich text box control:

Private Sub OpenToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles OpenToolStripMenuItem.Click

 

    If rtbDoc.Modified Then

 

        Dim answer As Integer

        answer = MessageBox.Show("The current document has not been

        saved, would you like to continue without saving?", "Unsaved

        Document", MessageBoxButtons.YesNo, MessageBoxIcon.Question)

 

        If answer = Windows.Forms.DialogResult.No Then

            Exit Sub

        Else

            OpenFile()

        End If

    Else

        OpenFile()

    End If

 

End Sub

This subroutine works in a manner similar to the "new" subroutine discussed in the previous section.  If the file has not been modified or if the user decides not to save the current modifications, the subroutine calls an Open File subroutine which in turn exposes a File Open dialog used to allow the user to navigate to the file they wish to open.  The Open File subroutine is next and contains this code:

Private Sub OpenFile()

 

    OpenFileDialog1.Title = "RTE - Open File"

    OpenFileDialog1.DefaultExt = "rtf"

    OpenFileDialog1.Filter = "Rich Text Files|*.rtf|Text Files|*.txt|HTML

    Files|*.htm|All Files|*.*"

    OpenFileDialog1.FilterIndex = 1

    OpenFileDialog1.ShowDialog()

 

    If OpenFileDialog1.FileName = "" Then Exit Sub

 

    Dim strExt As String

    strExt = System.IO.Path.GetExtension(OpenFileDialog1.FileName)

    strExt = strExt.ToUpper()

 

    Select Case strExt

        Case ".RTF"

            rtbDoc.LoadFile(OpenFileDialog1.FileName,

            RichTextBoxStreamType.RichText)

        Case Else

            Dim txtReader As System.IO.StreamReader

            txtReader = New

            System.IO.StreamReader(OpenFileDialog1.FileName)

            rtbDoc.Text = txtReader.ReadToEnd

            txtReader.Close()

            txtReader = Nothing

            rtbDoc.SelectionStart = 0

            rtbDoc.SelectionLength = 0

    End Select

 

    currentFile = OpenFileDialog1.FileName

    rtbDoc.Modified = False

    Me.Text = "Editor: " & currentFile.ToString() 

End Sub

WordProcessing7.gif

Figure 7:  Open File Dialog

The first part of the File Open subroutine is used to configure and display the Open File Dialog box; this code sets up the filters for the files types (rich text, text, or html), sets the dialog box title, and a selects an extension filter (rtf).  Once this is done, the dialog box is displayed, if the user Okays the dialog box without specifying a file name, the subroutine will exit.  If a file name exists, the code extracts the file extension from the file name, places the extension in a local string variable, converts it to upper case and does a select case statement on the string variable.  If the file selected by the user is an RTF file, the subroutine calls the control's Load File method and passes it the file name and format.  If the file is not an RTF file, a stream reader is instanced and passed the path to the file, the control is then fed the content of the file by means of the stream reader's read to end method.  The reader is then closed and disposed of and the cursor is moved to the beginning of the document and the selection length is set to zero (if you do not do this, the whole document will initialize as entirely selected).  After the file is loaded, the "currentFile" variable is updated to contain the current file path and name, the modified property of the control is set to false, and the caption bar is updated to show the name of the file currently under edit in the rich text box control.

The next item up is the "Save" menu option; it contains the following code:

Private Sub SaveToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles SaveToolStripMenuItem.Click

 

    If currentFile = "" Then

        SaveAsToolStripMenuItem_Click(Me, e)

        Exit Sub

    End If

 

    Dim strExt As String

    strExt = System.IO.Path.GetExtension(currentFile)

    strExt = strExt.ToUpper()

 

    Select Case strExt

        Case ".RTF"

            rtbDoc.SaveFile(currentFile)

        Case Else

            ' to save as plain text

            Dim txtWriter As System.IO.StreamWriter

            txtWriter = New System.IO.StreamWriter(currentFile)

            txtWriter.Write(rtbDoc.Text)

            txtWriter.Close()

            txtWriter = Nothing

            rtbDoc.SelectionStart = 0

            rtbDoc.SelectionLength = 0

            rtbDoc.Modified = False

    End Select

 

    Me.Text = "Editor: " & currentFile.ToString() 

End Sub

The "Save" function first checks to see if the "currentFile" variable is empty; if it is, the content of the rich text box control has not been saved previously and the subroutine will call the "Save As" menu option to provide the user with an interface to define a file name and storage location for the current unnamed file.  If the file is named (and has a current storage location), the subroutine will check the file extension and, by means of a Select Case statement, determine the appropriate method for storing the file and will then save the content to the file location.  This all works very similarly to the approach used to open the file however instead of opening a file, the approach is used to call the rich text box control's Save File method if the file is a rich text file, or to instance a stream writer and write the file content out as text to the file location if the file is plain text or html.

With both the file open and file save methods used, if the file is anything other than a rich text file, the application will attempt to open or save it with a stream reader or stream writer; this will allow the application to work with any text file, not just rtf, txt, or html extension files.  That would permit you to use it with custom file types or other things such as license files or error log files.

The next subroutine addresses the "Save As" menu option; its code is as follows:

Private Sub SaveAsToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles SaveAsToolStripMenuItem.Click

 

    SaveFileDialog1.Title = "RTE - Save File"

    SaveFileDialog1.DefaultExt = "rtf"

    SaveFileDialog1.Filter = "Rich Text Files|*.rtf|Text Files|*.txt|HTML

    Files|*.htm|All Files|*.*"

    SaveFileDialog1.FilterIndex = 1

    SaveFileDialog1.ShowDialog()

 

    If SaveFileDialog1.FileName = "" Then Exit Sub

 

    Dim strExt As String

    strExt = System.IO.Path.GetExtension(SaveFileDialog1.FileName)

    strExt = strExt.ToUpper()

 

    Select Case strExt

        Case ".RTF"

            rtbDoc.SaveFile(SaveFileDialog1.FileName,

            RichTextBoxStreamType.RichText)

        Case Else

            Dim txtWriter As System.IO.StreamWriter

            txtWriter = New

            System.IO.StreamWriter(SaveFileDialog1.FileName)

            txtWriter.Write(rtbDoc.Text)

            txtWriter.Close()

            txtWriter = Nothing

            rtbDoc.SelectionStart = 0

            rtbDoc.SelectionLength = 0

    End Select

 

    currentFile = SaveFileDialog1.FileName

    rtbDoc.Modified = False

    Me.Text = "Editor: " & currentFile.ToString() 

End Sub

WordProcessing8.gif

Figure 8:  File Menu Options

By now this should look pretty familiar; in the code, a save as file dialog box is configured  and displayed to the user.  The dialog will permit the user to save the file as rtf, txt, or html.  If the user saves the file as rtf, the control's save file method is used to store the contents of the file whilst preserving the rtf formatting.  If the user selects another option, the file will be saved as plain text using a text writer.  In either case, after the file is saved, the "currentFile" variable is updated, the application's title bar is updated, and the document's modified property is set to false.

The next item in the code is the menu's Exit call.  It is used to terminate the application.  Prior to closing the application, this subroutine checks to see if the current document has been modified and, if it has, it alerts the user and asks whether or not the document should be saved prior to closing it and the application.  The code is as follows:

Private Sub ExitToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles ExitToolStripMenuItem.Click

 

    If rtbDoc.Modified Then

 

        Dim answer As Integer

        answer = MessageBox.Show("The current document has not been

        saved, would you like to continue without saving?", "Unsaved

        Document", MessageBoxButtons.YesNo, MessageBoxIcon.Question)

 

        If answer = Windows.Forms.DialogResult.No Then

            Exit Sub

        Else

            Application.Exit()

        End If

    Else

        Application.Exit()

    End If 

End Sub

The next menu option addressed is the edit menu's "Select All" function.  Select All is a method embedded in the rich text box control and therefore it may be called directly without writing any additional code to make the select all happen; to use it, just call it as follows:

Private Sub SelectAllToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SelectAllToolStripMenuItem.Click

 

        Try

            rtbDoc.SelectAll()

        Catch exc As Exception

            MessageBox.Show("Unable to select all document content.", "RTE-

            Select", MessageBoxButtons.OK, MessageBoxIcon.Error)

        End Try

 

End Sub

 

Following the edit menu's "Select All" function, we have the cut, copy, and paste subroutines.  Just as the Select All method exists within the rich text box control, so do these and so you can call them directly in a manner similar to that used in Select All, for that reason, I am not going to show them here but you can see the calls made in the example application if you'd care to take a look at them.

WordProcessing9.gif

Figure 9:  Edit Menu Options

Next up is the menu option used to select the current font.  This code merely uses a standard font dialog box to set the rich text box control's selection font property to the font selected by the user through the font dialog.  The code used to do this is as follows:

Private Sub SelectFontToolStripMenuItem_Click(ByVal sender As

    System.Object, ByVal e As System.EventArgs) Handles

    SelectFontToolStripMenuItem.Click

 

    If Not rtbDoc.SelectionFont Is Nothing Then

        FontDialog1.Font = rtbDoc.SelectionFont

    Else

        FontDialog1.Font = Nothing

    End If

 

    FontDialog1.ShowApply = True

    If FontDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then

        rtbDoc.SelectionFont = FontDialog1.Font

    End If

 

End Sub

 

WordProcessing10.gif

 

Figure 10:  Font Dialog in Use

Similarly the font color menu option is used to display a standard color dialog to the user; if the user selects a color from the dialog, the fore color property of the document will be updated to contain the selected color.  As the rich text box control works primarily with selected text (that is, what you change in terms of selecting a font or changing a color), this function will alter the color only of the selected text.  If no text is selected, the color at the insertion point will hold the fore color selection and typing from the insertion point will show text in the newly selected color.

Private Sub FontColorToolStripMenuItem_Click(ByVal sender As

    System.Object, ByVal e As System.EventArgs) Handles

    FontColorToolStripMenuItem.Click

 

    ColorDialog1.Color = rtbDoc.ForeColor

    If ColorDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then

        rtbDoc.SelectionColor = ColorDialog1.Color

    End If

 

End Sub

 

The next three sections of code are the subroutines used to set the selected text's bold, italic, or underline properties.  Each section is set up to work such that, if the selected text is bold, selecting the bold option will remove the bolding (or italics, or underline).   (As they all basically work the same, I am only showing bold here)

 

Private Sub BoldToolStripMenuItem_Click(ByVal sender As System.Object,

    ByVal e As System.EventArgs) Handles BoldToolStripMenuItem.Click

    If Not rtbDoc.SelectionFont Is Nothing Then

        Dim currentFont As System.Drawing.Font = rtbDoc.SelectionFont

        Dim newFontStyle As System.Drawing.FontStyle

        If rtbDoc.SelectionFont.Bold = True Then

            newFontStyle = FontStyle.Regular

        Else

            newFontStyle = FontStyle.Bold

        End If

 

        rtbDoc.SelectionFont = New Font(currentFont.FontFamily,

        currentFont.Size, newFontStyle)

    End If

End Sub

The "Normal" font menu option returns the selected text to a normal, unadorned format:   

Private Sub NormalToolStripMenuItem_Click(ByVal sender As System.Object,

    ByVal e As System.EventArgs) Handles NormalToolStripMenuItem.Click

    If Not rtbDoc.SelectionFont Is Nothing Then

        Dim currentFont As System.Drawing.Font = rtbDoc.SelectionFont

        Dim newFontStyle As System.Drawing.FontStyle

        newFontStyle = FontStyle.Regular

 

        rtbDoc.SelectionFont = New Font(currentFont.FontFamily,

        currentFont.Size, newFontStyle)

    End If

End Sub

The menu option used to set the page color is used to expose a color dialog box to the user; if the user selects a color form the dialog, the back color of the rich text box control is set to that color.  The code to support this function is as follows:

Private Sub PageColorToolStripMenuItem_Click(ByVal sender As

    System.Object, ByVal e As System.EventArgs) Handles

    PageColorToolStripMenuItem.Click

        ColorDialog1.Color = rtbDoc.BackColor

    If ColorDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then

        rtbDoc.BackColor = ColorDialog1.Color

    End If

End Sub

WordProcessing11.gif

Figure 11:  Color Dialog in Use

The undo and redo functions are used to back up or restore changes made to the content of the control during an edit; the rich text box control supports the undo and redo function directly so all you need to do in order to add undo and redo support is merely evoke the method directly from the control, to make the call, test to determine whether or not the control can execute the undo or redo request, and, if it is supported, call the method:

Private Sub mnuUndo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuUndo.Click

    If rtbDoc.CanUndo Then rtbDoc.Undo()

End Sub

 

Private Sub mnuRedo_Click(ByVal sender As System.Object, ByVal e As

    System.EventArgs) Handles mnuRedo.Click

    If rtbDoc.CanRedo Then rtbDoc.Redo()

End Sub

 

The next three sections of code address setting the document's horizontal alignment property to support left, centered, or right justification of the selected text.  Each of these alignment control options is directly supported by the control:

 

Private Sub LeftToolStripMenuItem_Click_1(ByVal sender As System.Object,

    ByVal e As System.EventArgs) Handles LeftToolStripMenuItem.Click

    rtbDoc.SelectionAlignment = HorizontalAlignment.Left

End Sub

 

Private Sub CenterToolStripMenuItem_Click_1(ByVal sender As

    System.Object, ByVal e As System.EventArgs) Handles

    CenterToolStripMenuItem.Click

    rtbDoc.SelectionAlignment = HorizontalAlignment.Center

End Sub

 

Private Sub RightToolStripMenuItem_Click_1(ByVal sender As System.Object,

    ByVal e As System.EventArgs) Handles RightToolStripMenuItem.Click

        rtbDoc.SelectionAlignment = HorizontalAlignment.Right
End Sub

WordProcessing12.gif

Figure 12:  Alignment Options

Adding and removing bullets is also directly supported by the control, the Bullet Indent property sets the gap between the bullet and the text, the Selection Bullet property merely instructs the control to add or remove the bullet from the selected text:

Private Sub AddBulletsToolStripMenuItem_Click(ByVal sender As

System.Object, ByVal e As System.EventArgs) Handles

AddBulletsToolStripMenuItem.Click

    rtbDoc.BulletIndent = 10

    rtbDoc.SelectionBullet = True

End Sub

 

Private Sub RemoveBulletsToolStripMenuItem_Click(ByVal sender As

System.Object, ByVal e As System.EventArgs) Handles

RemoveBulletsToolStripMenuItem.Click

    rtbDoc.SelectionBullet = False

End Sub

WordProcessing13.gif

Figure 13:  Bullet Options

Setting the indentation level for the selected text is also directly supported by the control:

Private Sub mnuIndent0_Click(ByVal sender As System.Object, ByVal e As

System.EventArgs) Handles mnuIndent0.Click

    rtbDoc.SelectionIndent = 0

End Sub

WordProcessing14.gif

Figure 14:  Indentation Options

The application contains a separate dialog box used to find a text string within the current document, if the user selects the find menu option, the application will create and display a new instance of the search form (frmFind.vb):

Private Sub FindToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles FindToolStripMenuItem.Click

    Dim f As New frmFind()

    f.Show()

End Sub

 

Similarly, if the user selects the find and replace menu option, the application will create and display a new instance of the find and replace form (frmReplace.vb):

 

Private Sub FindAndReplaceToolStripMenuItem_Click(ByVal sender As

System.Object, ByVal e As System.EventArgs) Handles

FindAndReplaceToolStripMenuItem.Click

    Dim f As New frmReplace()

    f.Show()

End Sub

 

The print document is set to contain the content of the current rich text box control as the print document; in order to support print preview, page setup, and printing, given the modifications made to the extended rich text box control, all that needs to be done is to pass the print document to each of the related standard dialog boxes:

 

Private Sub PreviewToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles PreviewToolStripMenuItem.Click

    PrintPreviewDialog1.Document = PrintDocument1

    PrintPreviewDialog1.ShowDialog()

End Sub

 

Private Sub PrintToolStripMenuItem_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles PrintToolStripMenuItem.Click

    PrintDialog1.Document = PrintDocument1

    If PrintDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then

        PrintDocument1.Print()

    End If

End Sub

 

Private Sub mnuPageSetup_Click(ByVal sender As System.Object, ByVal e As    

System.EventArgs) Handles mnuPageSetup.Click

    PageSetupDialog1.Document = PrintDocument1

    PageSetupDialog1.ShowDialog()

End Sub

The next subroutine is a little more interesting; it is used to embed an image file into the extended rich text box document.  This subroutine uses a open file dialog box set to filter for the extensions used for bitmaps, jpegs, and gif files.  The user may navigate to the file that they want to embed into the document (placing it at the insertion point defined by the cursor).

Private Sub InsertImageToolStripMenuItem_Click(ByVal sender As

System.Object, ByVal e As System.EventArgs) Handles

InsertImageToolStripMenuItem.Click

 

    OpenFileDialog1.Title = "RTE - Insert Image File"

    OpenFileDialog1.DefaultExt = "rtf"

    OpenFileDialog1.Filter = "Bitmap Files|*.bmp|JPEG Files|*.jpg|GIF

    Files|*.gif"

    OpenFileDialog1.FilterIndex = 1

    OpenFileDialog1.ShowDialog()

 

    If OpenFileDialog1.FileName = "" Then Exit Sub

 

    Try

        Dim strImagePath As String = OpenFileDialog1.FileName

        Dim img As Image

        img = Image.FromFile(strImagePath)

        Clipboard.SetDataObject(img)

        Dim df As DataFormats.Format

        df = DataFormats.GetFormat(DataFormats.Bitmap)

        If Me.rtbDoc.CanPaste(df) Then

            Me.rtbDoc.Paste(df)

        End If

    Catch ex As Exception

        MessageBox.Show("Unable to insert image format selected.", "RTE-

        Paste", MessageBoxButtons.OK, MessageBoxIcon.Error)

    End Try 

End Sub

WordProcessing15.gif

Figure 15:  Embedding an Image File

Once the user selects a file through the open file dialog, the subroutine will create an image using the Image.FromFile method.  This image is then placed into the clipboard and subsequently pasted into the document.

The last section of the main form's code is contained in the printing region.  The calls used to print, due to the use of the extended rich text box control are very simple:

Private Sub PrintDocument1_BeginPrint(ByVal sender As Object, ByVal e As

System.Drawing.Printing.PrintEventArgs) Handles PrintDocument1.BeginPrint

    ' Adapted from Microsoft's example for extended richtextbox control

    '

    checkPrint = 0

End Sub

 

The Begin Print subroutine is used to set the "checkPrint" variable back to zero at the start of each new print job.

The Print Page subroutine evokes the extended rich text box control's print method to send the entire or selected section of the current document to the printer.  The call also checks to see if more than a single page exists and it will continue to print until all of the pages have been passed to the printer.  The code used to print is as follows:

Private Sub PrintDocument1_PrintPage(ByVal sender As Object, ByVal e As

System.Drawing.Printing.PrintPageEventArgs) Handles

PrintDocument1.PrintPage

 

    ' Adapted from Microsoft's example for extended richtextbox control

    '

    ' Print the content of the RichTextBox. Store the last character

      printed.

    checkPrint = rtbDoc.Print(checkPrint, rtbDoc.TextLength, e)

 

    ' Look for more pages

    If checkPrint < rtbDoc.TextLength Then

        e.HasMorePages = True

    Else

        e.HasMorePages = False

    End If

 

End Sub

WordProcessing16.gif

Figure 16:  Print Preview

The print section wraps up the rest of the main form class.

Code: The Find and Replace Form.

The find and replace form is supported with the frmReplace.vb class.  The find class is defined in frmFind.vb but since it contains two subroutines (find and find next) which are also contained in the find and replace form, I will only discuss the code contained in the find and replace form.

The find and replace form supports four subroutines:

  • Find
  • Find Next
  • Replace
  • Replace All

The find subroutine is pretty straight forward, it will search the entire document for the first occurrence of the search term defined by the user on the form.  It will search in one of two ways: With or without matching the case of the search term.  Depending upon whether or not the user has checked the Match Case check box on the form, the application will search for the text using either the binary or text compare method.  With the binary method, the search term must match exactly (including case), with the text compare method, the strings just need to match.  The "StartPosition" integer value is set to the value returned by from the InStr call; InStr is passed the starting position of 1, the entire body of text contained in the rich text box control (as the article to search), the search term entered by the user, and the search compare method).  InStr will return the index position of the found text if the text is in fact found, if nothing is found, it will return a zero.  If the starting position value is zero, the user will be notified that the search term was not found, else, the application will highlight the found text in the document, pan to its location, and set the focus back to the main form (which in turn makes the highlighting visible to the user).
 

Private Sub btnFind_Click(ByVal sender As System.Object, ByVal e As

System.EventArgs) Handles btnFind.Click

 

    Dim StartPosition As Integer

    Dim SearchType As CompareMethod

 

    If chkMatchCase.Checked = True Then

        SearchType = CompareMethod.Binary

    Else

        SearchType = CompareMethod.Text

    End If

 

    StartPosition = InStr(1, frmMain.rtbDoc.Text, txtSearchTerm.Text,

    SearchType)

 

    If StartPosition = 0 Then

        MessageBox.Show("String: '" & txtSearchTerm.Text.ToString() & "'

        not found", "No Matches", MessageBoxButtons.OK,

        MessageBoxIcon.Asterisk)

        Exit Sub

    End If

 

    frmMain.rtbDoc.Select(StartPosition - 1, txtSearchTerm.Text.Length)

    frmMain.rtbDoc.ScrollToCaret()

    frmMain.Focus() 

End Sub

The find next function works in a manner consistent with the find function; the only difference is that it sets the start position to the current position of the selection starting point within the document so that the find next function will not start at the beginning of the document each time it searches:

Private Sub btnFindNext_Click(ByVal sender As System.Object, ByVal e As

System.EventArgs) Handles btnFindNext.Click

 

    Dim StartPosition As Integer = frmMain.rtbDoc.SelectionStart + 2

    Dim SearchType As CompareMethod

 

    If chkMatchCase.Checked = True Then

        SearchType = CompareMethod.Binary

    Else

        SearchType = CompareMethod.Text

    End If

 

    StartPosition = InStr(StartPosition, frmMain.rtbDoc.Text,

    txtSearchTerm.Text, SearchType)

 

    If StartPosition = 0 Then

        MessageBox.Show("String: '" & txtSearchTerm.Text.ToString() & "'

        not found", "No Matches", MessageBoxButtons.OK,

        MessageBoxIcon.Asterisk)

        Exit Sub

    End If

 

    frmMain.rtbDoc.Select(StartPosition - 1, txtSearchTerm.Text.Length)

    frmMain.rtbDoc.ScrollToCaret()

    frmMain.Focus() 

End Sub

The replace subroutine is quite simple, it merely tests to see if any text is selected and, if it is, it replaces with the replacement text entered into the form by the user, it then moves to the next occurrence of the search term if one exists:

Private Sub btnReplace_Click(ByVal sender As System.Object, ByVal e As

System.EventArgs) Handles btnReplace.Click

 

    If frmMain.rtbDoc.SelectedText.Length <> 0 Then

        frmMain.rtbDoc.SelectedText = txtReplacementText.Text

    End If

 

    Dim StartPosition As Integer = frmMain.rtbDoc.SelectionStart + 2

    Dim SearchType As CompareMethod

 

    If chkMatchCase.Checked = True Then

        SearchType = CompareMethod.Binary

    Else

        SearchType = CompareMethod.Text

    End If

 

    StartPosition = InStr(StartPosition, frmMain.rtbDoc.Text,

    txtSearchTerm.Text, SearchType)

 

    If StartPosition = 0 Then

        MessageBox.Show("String: '" & txtSearchTerm.Text.ToString() & "'

        not found", "No Matches", MessageBoxButtons.OK,

        MessageBoxIcon.Asterisk)

        Exit Sub

    End If

 

    frmMain.rtbDoc.Select(StartPosition - 1, txtSearchTerm.Text.Length)

    frmMain.rtbDoc.ScrollToCaret()

    frmMain.Focus()

End Sub

The replace all function is a little different in that it uses a the replace method to replace every instance of the search term with the replacement term throughout the entire body of text:

Private Sub btnReplaceAll_Click(ByVal sender As System.Object, ByVal e As

System.EventArgs) Handles btnReplaceAll.Click

 

    Dim currentPosition As Integer = frmMain.rtbDoc.SelectionStart

    Dim currentSelect As Integer = frmMain.rtbDoc.SelectionLength

 

    frmMain.rtbDoc.Rtf = Replace(frmMain.rtbDoc.Rtf,

    Trim(txtSearchTerm.Text), Trim(txtReplacementText.Text))

    frmMain.rtbDoc.SelectionStart = currentPosition

    frmMain.rtbDoc.SelectionLength = currentSelect

    frmMain.Focus() 

End Sub

Again, the frmFind.vb class is the same as the replace class with the exception being that it does not support the replace and replace all methods.

Code:  Rich Text Box Print Control.

The code in the class library contained in the RichTextBoxPrintCtrl.vb class was developed at Microsoft; for a complete description of the content of the class, please refer to this link in you Visual Studio 2005 help files:

MS-HELP://MS.VSCC.V80/MS.MSDN.V80/MS.KB.V10.EN/ENU_KBVBNETKB/VBNETKB/811401.HTM

Summary.

This article and sample application have attempted to demonstrate some of the available techniques useful in creating and managing text and text files through the use of the rich text box control.  The control itself was modified using an approach recommended by Microsoft to greatly facilitate the ease with which one may print the contents of the text or rich text file.  Further, the application provided an approach to inserting an image into the rich text box as a means of creating a more useful application based upon the rich text box control.