Introduction to the Rich Text

Description

To support a rich text, the .NET Framework provides the RichTextBox control that is implement from the RichTextBox class. Like TextBox, the RichTextBox class is based on TextBoxBase. Therefore, to have right text in an application, from the Common Controls section of the Toolbox, click RichTextBox and click the form.

To programmatically create rich text, declare a variable of type RichTextBox, use the new operator to allocate memory for it, and add it to the Controls collection of its parent. Here is an example:

Imports System.Drawing
Imports System.Windows.Forms

Module Exercise

    Public Class Starter
        Inherits Form

        Private rchNote As RichTextBox

        Dim components As System.ComponentModel.Container

        Public Sub New()
            InitializeComponent()
        End Sub

        Public Sub InitializeComponent()

            rchNote = New RichTextBox()

            Controls.Add(rchNote)

        End Sub

    End Class

    Function Main() As Integer

        Dim frmStart As Starter = New Starter

        Application.Run(frmStart)

        Return 0
    End Function

End Module

1. Start Microsoft Visual Basic and create a new Windows Application named Notice1
2. In the Solution Explorer, right-click Form1.cs and click Rename
3. Type Editor.vb as the new name of the form and press Enter
4. From the Dialogs section of the Toolbox, click OpenFileDialog and click the form
5. In the Properties window, click DefaultExt and type rtf
6. Click (Name) and type dlgOpen
7. Click Filter and type Rich Text Format (*.rtf)|*.rtf|Text File (*.txt)|*.txt|All Files|
8. From the Dialogs section of the Toolbox, click SaveFileDialog and click the form
9. In the Properties window, click DefaultExt and type rtf
10. Click (Name) and type dlgSave
11. Click Filter and type Rich Text Format (*.rtf)|*.rtf|Text File (*.txt)|*.txt|All Files|
12. From the Common Controls section of the Toolbox, click RichTextBox and click the form
13. From the Menus & Toolbars section of the Toolbox, click MenuStrip and click the form
14. On the form, click Type Here, type File and press Enter
15. Under File, click Type Here, type New and press Enter
16. On the right side of File, click Type Here, type Edit and press Enter
17. Under Edit, click Type Here, type New and press Enter
18. In the same way, complete the menu strip with the following items:
     
19. On the form and click the rich text control
20. In the Properties window, change the its properties as follows:
    Name: rchEditor
    AcceptsTab: True
    Font: Times New Roman, 12pt
    Dock: Fill
    ScrollBars: Vertical
21. Right-click the form and click View Code
22. In the Class Name combo box, select (Editor Events)
23. In the Method Name combo box, select Load and change the file as follows:
     

    Imports System.IO Public Class Editor Private CurrentFileName As String Private Sub Form1_Load(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles Me.Load CurrentFileName = "<Not Allowed>" rchEditor.Modified = False End Sub End Class

24. In the Class Name combo box, select mnuEdit Undo
25. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuEditUndo_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuEditUndo.Click rchEditor.Undo() End Sub

26. In the Class Name combo box, select mnuEditRedo
27. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuEditRedo_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuEditUndo.Click rchEditor.Redo() End Sub

28. In the Class Name combo box, select mnu Edit Cut
29. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuEditCut_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuEditCut.Click rchEditor.Cut() End Sub

30. In the Class Name combo box, select mnu Edit Copy
31. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuEditCopy_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuEditCopy.Click rchEditor.Copy() End Sub

32. In the Class Name combo box, select mnu Edit Paste
33. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuEditPaste_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuEditPaste.Click rchEditor.Paste() End Sub

34. In the Class Name combo box, select mnuEdit Select All
35. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuSelectAll_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuSelectAll.Click rchEditor.SelectAll() End Sub

36. In the Class Name combo box, select mnu Format Word Wrap
37. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuFormatWordWrap_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatWordWrap.Click rchEditor.WordWrap = True End Sub

38. Save all

Like the other graphical Windows controls, the right text box uses the common characteristics such as the location, the size, the minimum size, the maximum size, the anchor, the docking, the font, the ability to be visible or hidden, the ability to be enabled or disabled, and the border style. Like the TextBox control, the rich text control inherits various characteristics from the TextBoxBase class, including the Text property, the Lines collection, the read-only attribute, the ability to select and manipulate text. The rich text box also shares various characteristics with the multi-line text box such as the Multiline property, the scroll bars, the word wrap, the ability to accept the Tab and the Enter keys. Here is an example:

Public Sub InitializeComponent()

            rchNote = New RichTextBox()
            rchNote.Size = New Size(Width, Height)
            rchNote.Multiline = True
            rchNote.ScrollBars = RichTextBoxScrollBars.Both
            rchNote.AcceptsTab = True
            rchNote.Font = New Font("Verdana", 10.0F)
            Dim strLines As String() = _
                  { _
                      "LeavingSydney", _
                      "When we decided to leave, we knew we were " & _
                      "making a hard decision. We had spent so much " & _
                      "time this had become our new home. A few " & _
                      "weeks or months before, we wanted to make " & _
                      "Sydney our newly found settlement, a " & _
                      "permanent place we could proudly call ours. " & _
                      "It appeared that, unpredictably, fate had " & _
                      "decided otherwise.", _
                      "Author: Arthur D. Pale", _
                      "Title: Stories Of My Life" _
                  }
            rchNote.Lines = strLines

            Controls.Add(rchNote)
            Controls.Add(rchNote)

End Sub

After creating and formatting a rich text document, you may want to save it for later use. To support this, the RichTextBox class provides a method named named SaveFile that is overloaded with three versions. One of the versions uses the following syntax:

Public Sub SaveFile(path As String)

This method takes as argument the name or path to a file. It will save the file as RTF. If you want the user to save a file that is either RTF, ASCII, or another format, to specify the desired format, you can use the following version of the method:

Public Sub SaveFile(data As Stream, fileType As RichTextBoxStreamType)

As seen in the first version, the first argument is the name or path of the file. The second argument allows you to specify the type of file that is being saved, which could be a normal ASCII text. This argument is of type RichTextBoxStreamType, which is an enumeration. The members of the RichTextBoxStreamType enumeration are PlainText, RichNoOleObjs, RichText, TextTextOleObjs, or TextTextOleObjs.

Instead of directly using the name of the file, you can create it as a stream. In this case, the RichTextBox class provides the following version of the SaveFile() method:

Public Sub SaveFile(path As String, fileType As RichTextBoxStreamType)

This version expects a Stream-based object such as a FileStream variable.

To assist you with opening a rich text file, the RichTextBox class is equipped with the LoadFile() method overloaded with three versions. The simplest versions has the following syntax:

Public Sub LoadFile(path As String)

This method takes as argument the name or path to a file. The file must be in RTF format. If it is not, the file will not be opened and the compiler would throw an IOException exception. If you want to give the user the ability to open different types of files, you should use the following version of the LoadFile() method:

Public Sub LoadFile(data As Stream, fileType As RichTextBoxStreamType)

The first argument is the same as a the single argument of the first version. The second argument allows you to specify the type of file that is being opened, which could be a normal ASCII text. This argument is of type RichTextBoxStreamType.

Instead of directly using the name of the file, you can create it as a stream. In this case, the RichTextBox class provides the following version of the LoadFile() method:

Public Sub LoadFile(path As String, fileType As RichTextBoxStreamType)

This version expects a Stream-based object such as a FileStream variable.

1. In the  Class Name combo box, click mnu File New
2. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFileNew_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFileNew.Click ' This is the question the user will have to answer Dim answer As MsgBoxResult = MsgBox( _ "The document has changed. Do you want to save it?" & _ vbCrLf & "Click\n" & _ "Yes:\tTo save the document and create a new one.\n" & _ "No:\tNot to save the document but create a new one.\n" & _ "Cancel:\tNot to do anything", _ MsgBoxStyle.YesNo Or MsgBoxStyle.Question, _ "Editor - Saving a File") ' When the user clicks File -> New to start a new document, ' before creating a new document, ' find out if the document is "dirty" ' sk the user whether to save or not If rchEditor.Modified = True Then ' Present the message box to the user who ' will decide whether to save If answer = MsgBoxResult.Yes Then ' If the user answers Yes ' Find out if the current document has never been saved If CurrentFileName = "<Not Allowed>" Then ' If it has never been saved, ' then display the Save dialog box If dlgSave.ShowDialog() = Windows.Forms.DialogResult.OK Then ' Save the file rchEditor.SaveFile(dlgSave.FileName) ' Change the current file name to something not allowed CurrentFileName = "<Not Allowed>" ' Display Untitled name of the ' current file on the title bar Text = "Parasol - Untitled" ' Since the document has been saved and the user wants ' to create a new one, empty the control rchEditor.Clear() ' Update the Modified attribute rchEditor.Modified = False Else ' the user had clicked Cancel, don't do anything Exit Sub End If Else ' If the document was saved before, then simply update it rchEditor.SaveFile(CurrentFileName) ' Change the current file name to something not allowed CurrentFileName = "<Not Allowed>" ' Display Untitled name of the current file on the title bar Text = "Parasol - Untitled" rchEditor.Clear() ' Update the Modified attribute rchEditor.Modified = False End If ElseIf answer = MsgBoxResult.No Then ' If the user answered No, ' then simply start a new document rchEditor.Clear() ' Change the current file name to something not allowed CurrentFileName = "<Not Allowed>" ' Display Untitled name of the current file on the title bar Text = "Parasol - Untitled" ' Update the Modified attribute rchEditor.Modified = False Else ' If the user clicked Cancel, don't do anything Exit Sub End If Else ' If the document was not modified, then start a new one ' If the user answered No, ' then simply start a new document rchEditor.Clear() ' Change the current file name to something not allowed CurrentFileName = "<Not Allowed>" ' Display Untitled name of the current file on the title bar Text = "Parasol - Untitled" ' Update the Modified attribute rchEditor.Modified = False End If End Sub

3. In the  Class Name combo box, click mnuFileOpen
4. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFileOpen_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFileOpen.Click ' Find out if there was a document and if the document was "dirty" If rchEditor.Modified = True Then ' Here is the question the user will answer Dim answer As MsgBoxResult = MsgBox( _ "The document has changed. Do you want to save it?" & _ vbCrLf & "Click\n" & _ "Yes:\tTo save the document and open a new one.\n" & _ "No:\tNot to save the document but open a new one.\n" & _ "Cancel:\tNot to do anything", _ MsgBoxStyle.YesNoCancel Or MsgBoxStyle.Question, _ "Editor - Opening a File") ' Find out if the user wants to save the current document If answer = MsgBoxResult.Yes Then ' Find out if this is a new document If CurrentFileName = "<Not Allowed>" Then ' Since the user wants to save the ' document, display the Save dialog box If dlgSave.ShowDialog() = _ Windows.Forms.DialogResult.OK Then ' Save the file rchEditor.SaveFile(dlgSave.FileName) Else Exit Sub End If else ' This was not a new document, ' so, simply save it rchEditor.SaveFile(CurrentFileName) End If ElseIf answer = MsgBoxResult.No Then ' If the user answered No to the question, don't save ' Simply open the file If dlgOpen.ShowDialog() = Windows.Forms.DialogResult.OK Then ' Open the new document after letting the user select it rchEditor.LoadFile(dlgOpen.FileName) ' Change the file name of our archives CurrentFileName = dlgOpen.FileName ' Get the name of the file that the user selected Dim fleParasol As FileInfo = _ New FileInfo(dlgOpen.FileName) Text = "Parasol - " & fleParasol.Name rchEditor.Modified = False Else Exit Sub End If else Exit Sub End If else If dlgOpen.ShowDialog() = Windows.Forms.DialogResult.OK Then ' Open the new document after letting the user select it rchEditor.LoadFile(dlgOpen.FileName) ' Change the file name of our archives CurrentFileName = dlgOpen.FileName ' Get the name of the file that the user selected Dim fleParasol As FileInfo = New FileInfo(dlgOpen.FileName) Text = "Parasol - " & fleParasol.Name rchEditor.Modified = False End If End If End Sub

5. In the  Class Name combo box, click mnuFileSave
6. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFileSave_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFileSave.Click ' Find out if the current document has never been saved ' but is not empty If (rchEditor.Modified = True) And _ (CurrentFileName = "<Not Allowed>") Then ' Since the document is dirty, display the Save As dialog box If dlgSave.ShowDialog() = Windows.Forms.DialogResult.OK Then ' Retrieve the new name file and display ' the file in the rich edit control rchEditor.SaveFile(dlgSave.FileName) ' Change/Update the global and complete name of the file, ' including its path CurrentFileName = dlgSave.FileName ' Extract the name of the file Dim fleParasol As FileInfo = New FileInfo(dlgSave.FileName) ' Display the name of the current file on the title bar Text = "Parasol - " & fleParasol.Name Else Exit Sub End If Else ' It appears that this document already had a name ' but the document was previously modified ' Therefore, simply save it internally rchEditor.SaveFile(CurrentFileName) End If End Sub

7. In the  Class Name combo box, click mnuFileSave As
8. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFileSaveAs_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFileSaveAs.Click If dlgSave.ShowDialog() = Windows.Forms.DialogResult.OK Then rchEditor.SaveFile(dlgSave.FileName) ' Change the file name of our archives CurrentFileName = dlgSave.FileName ' Get the name of the file that the user selected Dim fleParasol As FileInfo = New FileInfo(dlgSave.FileName) Text = "Parasol - " & fleParasol.Name rchEditor.Modified = False End If End Sub

9. In the  Class Name combo box, click mnuFile Exit
10. In the Method Name combo box, select Click and implement the event as follows:
     

    Private Sub mnuFileExit_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFileExit.Click ' Is the document dirty? If rchEditor.Modified = True Then ' Since the document is dirty, find out ' if the user wants to save it Dim Answer As MsgBoxResult = MsgBox( _ "The document has changed. Do you want to save it?" & _ vbCrLf & "Click\n" & _ "Yes:\tTo save the document and close the application.\n" & _ "No:\tNot to save the document but close the application.\n" & _ "Cancel:\tNot to do anything", _ MsgBoxStyle.YesNoCancel Or MsgBoxStyle.Question, _ "Parasol - Saving a File") ' If the user wants to save it If Answer = MsgBoxResult.Yes Then ' Behave as if the user had clicked File . Save mnuFileSave_Click(sender, e) Close() ElseIf Answer = MsgBoxResult.No Then ' If the user doesn't want to save the document Close() ' The user cancelled the action: do nothing Else Exit Sub End If Else ' There is no action to take Close() End If End Sub

11. Return to the form

We saw that you could change the general font of a text box and you can change the color of the characters. If you do this on a text box, all of the characters are changed to the same font and the same color. One of the extended properties of a rich text box over a regular text box is the ability to change the font and/ the color of individual characters, words, or paragraphs and the change applies only to the desired characters.

Before changing a character or a word, you must first select it. To change the font of the text that is selected on the control, the selected text is identified with the SelectionFont property. To change the color of the text that is selected, the selected text is identified with the SelectionColor property.

To assist you with this, you can use the Font dialog box. After selecting the character or word, you can transfer their attributes to the Font dialog box before displaying it. After using the dialog box, if the user clicks OK, you can retrieve the font and color characteristics then apply them to the selected character or text.

1. From the Dialogs section of the Toolbox, click FontDialog and click the form
2. Click (Name) and type dlgFont
3. Double-click ShowColor to set its value to True
4. Right-click the form and click View Code
5. In the Class Name combo box, select mnu Format Font
6. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFormatFont_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatFont.Click ' Get the characteristics of the selected text ' Apply them to the Font dialog box dlgFont.Font = rchEditor.SelectionFont dlgFont.Color = rchEditor.SelectionColor If dlgFont.ShowDialog() = Windows.Forms.DialogResult.OK Then ' Display the Font dialog box ' If the user clicks OK, get the characteristics of the font ' Apply them to the selected text of the Rich Edit control rchEditor.SelectionFont = dlgFont.Font rchEditor.SelectionColor = dlgFont.Color End If End Sub

7. Save all

For a text-based control, a paragraph is a series of words that start with a letter or empty space until the flow of text is interrupted, which is usually made with a carriage return, or the end of the document. By itself, the paragraph controls its alignment and such details as Tab measurements or indentation. To set or change the properties of a paragraph, you must first select it. To select a paragraph, you don't need to formally select it or any portion of its text. As long as the cursor is positioned inside of the paragraph, any paragraph attribute you set or change would apply to the whole paragraph. To manipulate more than one paragraph at the same time, you or your user must select them. The paragraphs do not need to be wholly selected. As long as a section is selected on it, a paragraph is considered selected.

The most common property of a paragraph is its alignment, which states whether the paragraph is positioned to the left, the center, or the right. This characteristic is controlled by the SelectionAlignment property. The SelectionAlignment property is based on the HorizontalAlignment enumeration whose members are Left, Center, and Right. Because this property is applied on (individual) paragraphs, it is not available at design time.

To change the alignment at run time, assign the desired value to the SelectionAlignment property.

1. In the  Class Name combo box, click mnuFormat Align Left
2. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFormatAlignLeft_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatAlignLeft.Click rchEditor.SelectionAlignment = HorizontalAlignment.Left End Sub

3. In the  Class Name combo box, click mnuFormat Align Center
4. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFormatAlignCenter_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatAlignCenter.Click rchEditor.SelectionAlignment = HorizontalAlignment.Center End Sub

5. In the  Class Name combo box, click mnuFormat Align Right
6. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFormatAlignRight_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatAlignRight.Click rchEditor.SelectionAlignment = HorizontalAlignment.Right End Sub

7. Return to the form

Indentation is the number of empty characters that separate a paragraph edge from one of the borders of the rich text control. Indentation refers to the left side or the right side of a paragraph. Based on this, left indentation refers to the number of empty characters from the left border of the rich text control to the left edge of a paragraph. The rich text control provides indentation through various properties.

To support indentation from the left side of a paragraph, the RichTextBox class is equipped with a property named SelectionIndent property. To indent from the right side, the RichTextBox is equipped with the SelectionRightIndent property.

1. In the  Class Name combo box, click mnuFormat Left Indent
2. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFormatLeftIndent_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatLeftIndent.Click rchEditor.SelectionIndent += 10 End Sub

3. In the  Class Name combo box, click mnuFormat Right Indent
4. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub mnuFormatRightIndent_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatRightIndent.Click rchEditor.SelectionRightIndent += 10 End Sub

5. Return to the form

Instead of just a regular section made only of text, you can create an unordered list of lines or paragraphs in your document. To support this, the RichTextBox class is equipped with a Boolean property named SelectionBullet. If you set this property to false on a paragraph, the paragraph would start with a bullet. If you apply this property to more than one consecutive paragraph, each would start with a bullet.

1. In the  Class Name combo box, click mnu FormatBulletList
2. In the Method Name combo box, select Click and implement their Click events as follows:
    

   Private Sub mnuFormatBulletList_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles mnuFormatBulletList.Click rchEditor.SelectionBullet = True End Sub

3. Execute the application and test the editor
4. Close the form and return to your programming environment