Windows Forms RichTextBox
FAQ Home
1.
How can I create and save a RTF file?
2. How can I get a string that contains RTF format codes into
a RichTextBox?
3. How do I make the RichTextBox support drag and drop?
4. How do I set the color and font in a RichEditBox?
5. How can I change the FontStyle of a selection without
losing the styles that are present?
6. How can I programmatically position the cursor on a given
line and character of my richtextbox?
7. How can I load an embedded rich text file into a
richtextbox?
8. How can I print my rich text?
9. Where can I find more information on the RTF specification?
1 How can I create and save a RTF file?
One way to do this is to use the RichTextBox.SaveFile method.
private void
button1_Click(object sender, System.EventArgs e)
{
// Create a SaveFileDialog & initialize the RTF extension
SaveFileDialog saveFile1 = new SaveFileDialog();
saveFile1.DefaultExt = "*.rtf";
saveFile1.Filter = "RTF Files|*.rtf";
// get a file name from the user
if(saveFile1.ShowDialog() == DialogResult.OK)
{
// Save the RTF contents of the RichTextBox control that
// was dragged onto the Window Form and populated somehow
richTextBox1.SaveFile(saveFile1.FileName,
RichTextBoxStreamType.RichText); //use to save RTF tags
in file
//RichTextBoxStreamType.PlainText);//use to save plain
text in file
}
}
2 How can I get a string that contains RTF format codes
into a RichTextBox?
Use the Rtf property of the control.
richTextBox1.Rtf = @"{\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl{\f0\fswiss\fcharset0
Arial;}}\viewkind4\uc1\pard\b\i\f0\fs20 This is bold italics.\par }";
3 How do I make the RichTextBox support drag and drop?
1) Set the AllowDrop property to true
2) Add handlers for both the DragEnter and DragDrop event
this.richTextBox1.DragEnter +=
new System.Windows.Forms.DragEventHandler(this.richTextBox1_DragEnter);
this.richTextBox1.DragDrop += new
System.Windows.Forms.DragEventHandler(this.richTextBox1_DragEnter);
....
private void richTextBox1_DragEnter(object sender,
System.Windows.Forms.DragEventArgs e)
{
if (((DragEventArgs)e).Data.GetDataPresent(DataFormats.Text))
((DragEventArgs)e).Effect = DragDropEffects.Copy;
else
((DragEventArgs)e).Effect = DragDropEffects.None;
}
private void richTextBox1_DragDrop(object sender, DragEventArgs e)
{
// Loads the file into the control.
richTextBox1.LoadFile((String)e.Data.GetData("Text"),
System.Windows.Forms.RichTextBoxStreamType.RichText);
}
Here are VB snippets.
AddHandler
Me.richTextBox1.DragEnter, New
System.Windows.Forms.DragEventHandler(AddressOf Me.richTextBox1_DragEnter)
AddHandler Me.richTextBox1.DragDrop, New
System.Windows.Forms.DragEventHandler(AddressOf Me.richTextBox1_DragEnter)
.....
Private Sub richTextBox1_DragEnter(sender As Object, e As
System.Windows.Forms.DragEventArgs)
If CType(e, DragEventArgs).Data.GetDataPresent(DataFormats.Text)
Then
CType(e, DragEventArgs).Effect = DragDropEffects.Copy
Else
CType(e, DragEventArgs).Effect = DragDropEffects.None
End If
End Sub 'richTextBox1_DragEnter
Private Sub richTextBox1_DragDrop(sender As Object, e As DragEventArgs)
' Loads the file into the control.
richTextBox1.LoadFile(CType(e.Data.GetData("Text"), [String]),
System.Windows.Forms.RichTextBoxStreamType.RichText)
End Sub 'richTextBox1_DragDrop
4 How do I set the color and font in a RichEditBox?
You use the SelectionFont and SelectionColor properties. Make sure the
control had focus. Then the following code will set the currently selected
text to a red-bold-courier font. If no text is currently selected, then any
new text typed (or inserted) will be red-bold-courier.
[C#]
richTextBox1.Focus();
richTextBox1.SelectionColor = Color.Red;
richTextBox1.SelectionFont = new Font ("Courier", 10, FontStyle.Bold);
[VB.NET]
richTextBox1.Focus()
richTextBox1.SelectionColor = Color.Red
richTextBox1.SelectionFont = new Font ("Courier", 10, FontStyle.Bold)
5 How can I change the FontStyle of a selection without
losing the styles that are present?
If you visit the selection a character at the time, you can get the current
FontStyle and modify it directly to add or remove a style like Bold or
Italic. Doing it a character at a time will avoid losing the other styles
that are set. The problem with doing it a whole selection at a time is that
the FontStyle of the entire selection is the common styles set among all
characters in the selection. So, if one char is bold and one is not, then
bold is not set when you retrieve the fontstyle for the entire selection.
Doing things a character at the time, avoids this problem and allows things
to work OK. You can download a working sample(CS,VB).
private void AddFontStyle(FontStyle
style)
{
int start = richTextBox1.SelectionStart;
int len = richTextBox1.SelectionLength;
System.Drawing.Font currentFont;
FontStyle fs;
for(int i = 0; i < len; ++i)
{
richTextBox1.Select(start + i, 1);
currentFont = richTextBox1.SelectionFont;
fs = currentFont.Style;
//add style
fs = fs | style;
richTextBox1.SelectionFont = new Font(
currentFont.FontFamily,
currentFont.Size,
fs
);
}
}
private void RemoveFontStyle(FontStyle style)
{
int start = richTextBox1.SelectionStart;
int len = richTextBox1.SelectionLength;
System.Drawing.Font currentFont;
FontStyle fs;
for(int i = 0; i < len; ++i)
{
richTextBox1.Select(start + i, 1);
currentFont = richTextBox1.SelectionFont;
fs = currentFont.Style;
//remove style
fs = fs & ~style;
richTextBox1.SelectionFont = new Font(
currentFont.FontFamily,
currentFont.Size,
fs
);
}
}
private void button1_Click(object sender, System.EventArgs e)
{
AddFontStyle(FontStyle.Bold);
}
6 How can I programmatically position the cursor on a
given line and character of my richtextbox?
There are a couple different methods that can be used here. The first
changes focus, so may not be possible if you have controls that fire
validation. The second uses interop, which requires full trust.
Method 1: Eric Terrell suggested this solution in an email to
winformsfaq@syncfusion.com.
The richtextbox control contains a Lines array property, one entry for every
line. Each line entry has a Length property. With this information, you can
position the selection cursor using code such as:
private void
GoToLineAndColumn(RichTextBox RTB, int Line, int Column)
{
int offset = 0;
for (int i = 0; i < Line - 1 && i < RTB.Lines.Length; i++)
{
offset += RTB.Lines[i].Length + 1;
}
RTB.Focus();
RTB.Select(offset + Column, 0);
}
(Note: you may want to store this.ActiveControl to be retrieved after
calling Select()).
Method 2:
const int SB_VERT = 1;
const int EM_SETSCROLLPOS = 0x0400 + 222;
[DllImport("user32", CharSet=CharSet.Auto)]
public static extern bool GetScrollRange(IntPtr hWnd, int nBar, out int
lpMinPos, out int lpMaxPos);
[DllImport("user32", CharSet=CharSet.Auto)]
public static extern IntPtr SendMessage(IntPtr hWnd, int msg, int wParam,
POINT lParam);
[StructLayout(LayoutKind.Sequential)]
public class POINT
{
public int x;
public int y;
public POINT()
{
}
public POINT(int x, int y)
{
this.x = x;
this.y = y;
}
}
// Example -- scroll the RTB so the bottom of the text is always
visible.
int min, max;
GetScrollRange(richTextBox1.Handle, SB_VERT, out min, out max);
SendMessage(richTextBox1.Handle, EM_SETSCROLLPOS, 0, new POINT(0, max -
richTextBox1.Height));
7 How can I load an embedded rich text file into a richtextbox?
You use the LoadFile method of the RichTextBox, passing it a streamreader
based on the resource. So include your RTF file as an embedded resource in
your project, say RTFText.rtf. Then load your richtextbox with code such as
Stream stream = this.GetType().Assembly.GetManifestResourceStream("MyNameSpace.RTFText.rtf");
if (stream != null)
{
StreamReader sr = new StreamReader(stream);
richTextBox1.LoadFile(stream, RichTextBoxStreamType.RichText);
sr.Close();
}
Here is a VB snippet. Depending on your default namespace settings,
you may not need explicit reference to the namespace in the
GetManifestResourceStream argument.
Dim stream As Stream =
Me.GetType().Assembly.GetManifestResourceStream("MyNameSpace.RTFText.rtf")
If Not (stream Is Nothing) Then
Dim sr As New StreamReader(stream)
richTextBox1.LoadFile(stream, RichTextBoxStreamType.RichText)
sr.Close()
End If
8 How can I print my rich text?
There is no direct support for printing rich text in the .NET Framework. To
print it, you can use interop with the SendMessage API and these three
messages to do your printing.
EM_SETTARGETDEVICE : specify the target device
EM_FORMATRANGE : format part of a rich edit control's contents for a
specific device
EM_DISPLAYBAND : send the output to the device
For more information about these messages, see this Microsoft link on
RichTextControl. It has a bookmark to a Printing discussion.
Martin Muller has posted a C# solution using this technique on
http://www.codeguru.com/cs_controls/RichTextEx.phpl
9 Where can I find more information on the RTF
specification?
This site has a lot of good information on the RTF specification:
http://www.dubois.ws/software/RTF/.
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