A RichTextBox control is an advanced text box that provides text
editing and advanced formatting features including loading rich text format
(RTF) files.
In this article, I will demonstrates how create and use various
features of Windows Forms RichTextBox control.
Creating a RichTextBox
We
can create a RichTextBox control using a Forms designer at design-time or using
the RichTextBox class in code at run-time.
To
create a RichTextBox control at design-time, you simply drag and drop a RichTextBox
control from Toolbox onto a Form in Visual Studio. Once a RichTextBox is added
to a Form, you can move it around and resize it using mouse and set its
properties and events.
Creating a RichTextBox control at run-time is merely a work
of creating an instance of RichTextBox class, set its properties and add RichTextBox
class to the Form controls.
First step to create a dynamic RichTextBox is to create an
instance of RichTextBox class. The following code snippet creates a RichTextBox
control object.
Dim dynamicRichTextBox As New RichTextBox()
In the next step, you may set properties of a RichTextBox
control. The following code snippet sets size, location, background color,
foreground color, Text, Name, and Font properties of a RichTextBox.
dynamicRichTextBox.Location = New Point(20, 20)
dynamicRichTextBox.Width = 300
dynamicRichTextBox.Height = 200
'
Set background and foreground
dynamicRichTextBox.BackColor = Color.Red
dynamicRichTextBox.ForeColor = Color.Blue
dynamicRichTextBox.Text = "I
am Dynamic RichTextBox"
dynamicRichTextBox.Name = "DynamicRichTextBox"
dynamicRichTextBox.Font = New
Font("Georgia",
16)
Once a RichTextBox control
is ready with its properties, next step is to add the RichTextBox control to
the Form. To do so, we use Form.Controls.Add method. The following code snippet
adds a RichTextBox control to the current Form.
Controls.Add(dynamicRichTextBox)
RichTextBox control
looks like Figure 1.
Figure 1
Setting RichTextBox
Properties
After you place a RichTextBox control on a Form, the next step is
to set properties.
The easiest way to set properties is from the Properties Window.
You can open Properties window by pressing F4 or right click on a control and
select Properties menu item. The Properties window looks like Figure 2.
Figure 2
Location,
Height, Width, and Size
The Location property takes a Point that specifies the
starting position of the RichTextBox on a Form. The Size property specifies the
size of the control. We can also use Width and Height property instead of Size
property. The following code snippet sets Location, Width, and Height
properties of a RichTextBox control.
dynamicRichTextBox.Location = New Point(20, 20)
dynamicRichTextBox.Width = 300
dynamicRichTextBox.Height = 200
Background,
Foreground, BorderStyle
BackColor and ForeColor properties are used to set background and
foreground color of a RichTextBox respectively. If you click on these
properties in Properties window, the Color Dialog pops up.
Alternatively, you can set background and foreground colors at
run-time. The following code snippet sets BackColor and ForeColor properties.
dynamicRichTextBox.BackColor = Color.Red
dynamicRichTextBox.ForeColor = Color.Blue
You can also set borders style of a RichTextBox by using the
BorderStyle property. The BorderStyle property is represented by a BorderStyle
enumeration that has three values – FixedSingle, Fixed3D, and None. The default value of border style is Fixed3D. The
following code snippet sets the border style of a RichTextBox to FixedSingle.
dynamicRichTextBox.BorderStyle = BorderStyle.FixedSingle
Name
Name property represents a unique name of a RichTextBox
control. It is used to access the control in the code. The following code
snippet sets and gets the name and text of a RichTextBox control.
dynamicRichTextBox.Name = "DynamicRichTextBox"
Text and
TextLength
Text property of a RichTextBox represents the current text
of a RichTextBox control. The TextLength property returns the length of a RichTextBox
contents.
The following code snippet sets and gets the Text and TextLength
properties and gets the size of a RichTextBox control.
dynamicRichTextBox.Text = "I
am Dynamic RichTextBox"
Dim len As Integer = dynamicRichTextBox.TextLength
Append Text
One way to append text to a RichTextBox
is simply set Text property to current text plus new text you would want to
append something like this.
RichTextBox1.Text += "
Appended text"
RichTextBox also has the
ApendText method to do the same. The AppendText
method appends text at the end of a RichTextBox. The following code snippet
uses AppendText method to append text to the RichTextBox1 contents.
RichTextBox1.AppendText(" Appended
text")
AcceptsTab
If a RichTextBox control is set to multiline, the AcceptsTab
property is used to set so the RichTextBox control accepts TAB key. If this
property is not set, pressing TAB key simply move to the next control on a
Form. By default, AcceptsTab property value of a RichTextBox control is false.
dynamicRichTextBox.AcceptsTab = True
WordWrap
If WordWrap property is
true, the text in the RichTextBox control automatically wraps to the next line
if required. If this property is set to true,
horizontal scroll bars are not displayed regardless of the ScrollBars property
setting.
dynamicRichTextBox.WordWrap = True
ScrollBars
A Multiline RichTextBox control can have scrollbars. The
ScrollBars property of RichTextBox control is used to show scrollbars on a
control. The ScrollBars property is represented by a RichTextBoxScrollBars
enumeration that has four values – Both, Vertical, Horizontal, and None.
The following code snippet makes both vertical and horizontal
scrollbars active on a RichTextBox control and they will be visible when the
scrolling is needed on a RichTextBox control.
dynamicRichTextBox.ScrollBars = RichTextBoxScrollBars.Both
Font
Font property represents the font of text of a RichTextBox
control. If you click on the Font property in Properties window, you will see
Font name, size and other font options. The following code snippet sets Font
property at run-time.
dynamicRichTextBox.Font = New
Font("Georgia",
16)
Maximum
Length
You can restrict number of characters in a RichTextBox control by
setting MaxLength property. The following code snippet sets the maximum length
of a RichTextBox to 50 characters.
dynamicRichTextBox.MaxLength = 50
ReadOnly
You can make a RichTextBox control read-only (non-editable) by
setting the ReadOnly property to true. The following code snippet sets the
ReadOnly property to true.
dynamicRichTextBox.ReadOnly = True
Enabling and
Disabling Shortcuts
ShortcutsEnabled property of the RichTextBox is used to enable or
disable shortcuts. By default, shortcuts are enabled. The following code
snippet disables shortcuts in a RichTextBox.
dynamicRichTextBox.ShortcutsEnabled = False
ShortcutsEnabled
property applies to the following shortcut key combinations:
- CTRL+Z
- CTRL+E
- CTRL+C
- CTRL+Y
- CTRL+X
- CTRL+BACKSPACE
- CTRL+V
- CTRL+DELETE
- CTRL+A
- SHIFT+DELETE
- CTRL+L
- SHIFT+INSERT
- CTRL+R
Read
RichTextBox Contents
The simplest way of reading a RichTextBox control contents is
using the Text property. The following code snippet reads contents of a
RichTextBox in a string.
Dim RichTextBoxContents As String = dynamicRichTextBox.Text
In a multiline RichTextBox, if the RichTextBox contents are
separated by multiple lines and you want to read contents of a RichTextBox line
by line, you can use the Lines property of the RichTextBox. The Lines property
returns an array of strings where each element of the returned array is a line.
The following code snippet reads a RichTextBox contents line by
line.
Dim allLines() As String = dynamicRichTextBox.Lines
For lineCounter = 0 To
allLines.GetUpperBound(0)
MessageBox.Show(allLines(lineCounter))
Next
Selection in RichTextBox
SelectedText property returns the selected text in a RichTextBox
control.
Dim selectedText As String = dynamicRichTextBox.SelectedText
You may also use SelectionStart and SelectionLength properties to
get and set the selected text in a RichTextBox. The SelectionStart property
represents the starting index of the selected text and SelectionLength property
represents the number of characters to be selected after the starting
character. The following code snippet sets the selection on a RichTextBox.
dynamicRichTextBox.SelectionStart = 10
dynamicRichTextBox.SelectionLength = 20
Clear, SelectAll
and Deselect All
Clear method removes the
contents of a RichTextBox. The following code snippet uses Clear method to
clear the contents of a RichTextBox.
dynamicRichTextBox.Clear()
RichTextBox class provides
SelectAll and DeselectAll methods to select and deselect all text of a RichTextBox
control. The following code snippet shows how to use SelectAll and DeselectAll
methods.
dynamicRichTextBox.SelectAll()
dynamicRichTextBox.DeselectAll()
Summary
A RichTextBox control accepts user input on a Form and provides
rich text features. In this article, we discussed discuss how to create a RichTextBox
control in Windows Forms at design-time as well as run-time. After that, we saw
how to use various properties and methods.
Further Readings
Here is a list of more articles related to this topic.
·
Syntax
Highlighting in Rich TextBox Control - Part 1 by Duncan
Harris
·
Syntax
Highlighting in RichTextBox Control - Part 2 by Duncan
Harris
·
Part
I: Simple Color Syntax Code Editor for PHP written in C# and .NET by Mike
Gold
·
Exporting
a RichTextBox to a Microsoft Word Document by Mike
Gold
·
Opening
and Viewing Text and Image Files by Manisha
Mehta on Jan 11, 2006
·
Text
Editor in C# by Puran
Mehra on Jan 03, 2010