Links with arbitrary text in a RichTextBox

Glad you could use the code. Smile | :)

Putting additional information into the hidden text is a good idea. The only thing I'm a bit worried about (without trying out your suggestion yet) is what will happen when the text is modified. You'd have to adjust every position information after the point of modification, wouldn't you?

I've used a similar approach somewhere else where I store serialized objects in the hidden text and have to be sure the whole range including the "hyperlink" is intact all the time.
Protecting the text range was what I did in the end...

mav

You're absolutely right about position adjustment when modifying the text, glad you pointed out that because this is something we looked by in the rush. I'll post any solution we come up on this.. Smile | :)

Cheers / z3al0t

I'm doing exacly the same thing for a client. Please post the code. Thanks.

Paul

Hello Paul,

This is how we did our solution, it's not 100% satisfying but it work well enough to fill our needs. It allows us to show any links in a saved RTF-text, and lets us modify existing text without destroying the links in it.

First we modified the InsertLink method:

public void InsertLink(string text, string hyperlink, int position)<br />
{<br />
   if (position < 0 || position > this.Text.Length)<br />
      throw new ArgumentOutOfRangeException("position");<br />
<br />
   string startLinkStr = @"LINKSTART";<br />
   string endLinkStr = @"#LINKEND";<br />
<br />
   int linkStartPos = position - startLinkStr.Length;<br />
<br />
   this.SelectionStart = position;<br />
   this.SelectedRtf = @"{\rtf1\ansi \v LINKSTART\v0" + text + @"\v #" + hyperlink + @"#LINKEND\v0}";<br />
   this.Select(position, text.Length + hyperlink.Length + 1 + endLinkStr.Length + startLinkStr.Length);<br />
   this.SetSelectionLink(true);<br />
   this.Select(position + text.Length + hyperlink.Length + 1, 0);<br />
}

Then we wrote some own methods to be able to show the links in a RTF-text that has been loaded. First, one public method called ShowLinks that we trigger after the loading of RTF-text is completed:

public void ShowLinks()<br />
{<br />
   int curPos = 0;<br />
<br />
   string startTextStr = "LINKSTART";<br />
   string endTextStr = "#";<br />
   string endLinkStr = "#LINKEND";<br />
<br />
   while (RtfHasMoreLinks(curPos))<br />
   {<br />
      // Find hidden link text<br />
      int sPos = this.Text.IndexOf(startTextStr, curPos);<br />
      int hStartIndex = sPos;<br />
<br />
      sPos += startTextStr.Length;<br />
      int ePos = this.Text.IndexOf(endTextStr, sPos);<br />
<br />
      // Now we have the text of link<br />
      string linkText = this.Text.Substring(sPos, (ePos - sPos));<br />
<br />
      // Get the start position of link<br />
      int sLinkPos = ePos + endTextStr.Length;<br />
      int eLinkPos = this.Text.IndexOf(endLinkStr, sPos);<br />
<br />
      // The link<br />
      string hLink = this.Text.Substring(sLinkPos, (eLinkPos - sLinkPos));<br />
<br />
      int hEndIndex = eLinkPos + endLinkStr.Length;<br />
<br />
      // Show the link in box<br />
      ShowDistinctLink(hStartIndex, hEndIndex, linkText, hLink);<br />
<br />
      // Save the current end post at current position<br />
      curPos = eLinkPos;<br />
   }<br />
}

And then some private methods for the method above:

private bool RtfHasMoreLinks(int curPos)<br />
{<br />
   return (this.Text.IndexOf("LINKSTART", curPos) > curPos ? true : false);      <br />
}<br />
<br />
private void ShowDistinctLink(int sPos, int ePos, string displayText, string hyperlink)<br />
{<br />
   if (sPos < 0 || sPos > ePos)<br />
      throw new ArgumentOutOfRangeException("position");<br />
<br />
   this.Select(sPos, (ePos - sPos));<br />
   this.SetSelectionLink(true);<br />
   this.Select(sPos + displayText.Length + hyperlink.Length + 1, 0);<br />
}

Hope this can be to any help for you. Let me know if you find any bugs or flaws.. Smile | :)

Cheers / z3al0t

Hi,

Thats really good of you. I'll test the code and let you know how I get on.

Thanks again,

Paul Cookson

Hi mav, z3al0t and Paul,

this looks all like good work so far. I hope his hidden stuff technique solves several problems i have on my project.

1. Serializing and deserializing links.
2. Add information to the rtf so i can write a parser to convert my text into a proprietary xml format.
3. Add 'paragraph folding'. Currently i have the problem that i cannot match the unfold button to the part in the rtf it should unfold AFTER editing the text before the folded paragraph.

My previous approach to 2. and 3. was to guard all editing actions in the richtextbox. That approach failed to handle pasting of text. Maybe i just wasn't bright enough to do it properly. Confused | :confused:

Now i'm gonna test z3al0ts extension. Smile | :)

MfG
Sascha

What I do to stop editing from happening is to set a bool when I'm allowing the user to edit and when i'm not allowing the user to edit. Then, whenever the text is updated in the rtb i call rtb.undo when the bool is false. works like a charm.

Dear Sir,

I am Shibu Mathew. I checked your solution and it is really impressive. But unfortunately in that coding implementation it is not showing the link if I put
this.SelectedRtf = @"{\rtf1\ansi \v LINKSTART\v0" + text + @"\v #" + hyperlink + @"#LINKEND\v0}";

if it is
this.SelectedRtf = @"{\rtf1\ansi \vLINKSTART\v0" + text + @"\v #" + hyperlink + @"#LINKEND\v0}";
Then it showing link. Could you please send me any sample coding you made for showing the link.

Kindly send me in my email id : shibu.mathew@jgc.com.sa

I am using vb.net I converted the code into Vb.net

Imports System
Imports System.ComponentModel
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Runtime.InteropServices

Namespace RichTextBoxLinks
Public Class RichTextBoxExNew
Inherits RichTextBox
#Region "Interop-Defines"
<StructLayout(LayoutKind.Sequential)> _
Private Structure CHARFORMAT2_STRUCT
Public cbSize As UInt32
Public dwMask As UInt32
Public dwEffects As UInt32
Public yHeight As Int32
Public yOffset As Int32
Public crTextColor As Int32
Public bCharSet As Byte
Public bPitchAndFamily As Byte
<MarshalAs(UnmanagedType.ByValArray, SizeConst:=32)> _
Public szFaceName As Char()
Public wWeight As UInt16
Public sSpacing As UInt16
Public crBackColor As Integer
' Color.ToArgb() -> int
Public lcid As Integer
Public dwReserved As Integer
Public sStyle As Int16
Public wKerning As Int16
Public bUnderlineType As Byte
Public bAnimation As Byte
Public bRevAuthor As Byte
Public bReserved1 As Byte
End Structure

<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
End Function

Private Const WM_USER As Integer = &H400
Private Const EM_GETCHARFORMAT As Integer = WM_USER + 58
Private Const EM_SETCHARFORMAT As Integer = WM_USER + 68

Private Const SCF_SELECTION As Integer = &H1
Private Const SCF_WORD As Integer = &H2
Private Const SCF_ALL As Integer = &H4

#Region "CHARFORMAT2 Flags"
Private Const CFE_BOLD As UInt32 = &H1
Private Const CFE_ITALIC As UInt32 = &H2
Private Const CFE_UNDERLINE As UInt32 = &H4
Private Const CFE_STRIKEOUT As UInt32 = &H8
Private Const CFE_PROTECTED As UInt32 = &H10
Private Const CFE_LINK As UInt32 = &H20
Private Const CFE_AUTOCOLOR As UInt32 = &H40000000
Private Const CFE_SUBSCRIPT As UInt32 = &H10000
' Superscript and subscript are
Private Const CFE_SUPERSCRIPT As UInt32 = &H20000
' mutually exclusive

Private Const CFM_SMALLCAPS As Integer = &H40
' (*)
Private Const CFM_ALLCAPS As Integer = &H80
' Displayed by 3.0
Private Const CFM_HIDDEN As Integer = &H100
' Hidden by 3.0
Private Const CFM_OUTLINE As Integer = &H200
' (*)
Private Const CFM_SHADOW As Integer = &H400
' (*)
Private Const CFM_EMBOSS As Integer = &H800
' (*)
Private Const CFM_IMPRINT As Integer = &H1000
' (*)
Private Const CFM_DISABLED As Integer = &H2000
Private Const CFM_REVISED As Integer = &H4000

Private Const CFM_BACKCOLOR As Integer = &H4000000
Private Const CFM_LCID As Integer = &H2000000
Private Const CFM_UNDERLINETYPE As Integer = &H800000
' Many displayed by 3.0
Private Const CFM_WEIGHT As Integer = &H400000
Private Const CFM_SPACING As Integer = &H200000
' Displayed by 3.0
Private Const CFM_KERNING As Integer = &H100000
' (*)
Private Const CFM_STYLE As Integer = &H80000
' (*)
Private Const CFM_ANIMATION As Integer = &H40000
' (*)
Private Const CFM_REVAUTHOR As Integer = &H8000

Private Const CFM_BOLD As UInt32 = &H1
Private Const CFM_ITALIC As UInt32 = &H2
Private Const CFM_UNDERLINE As UInt32 = &H4
Private Const CFM_STRIKEOUT As UInt32 = &H8
Private Const CFM_PROTECTED As UInt32 = &H10
Private Const CFM_LINK As UInt32 = &H20
Private Const CFM_SIZE As UInt32 = &H8000000
Private Const CFM_COLOR As UInt32 = &H40000000
Private Const CFM_FACE As UInt32 = &H20000000
Private Const CFM_OFFSET As UInt32 = &H10000000
Private Const CFM_CHARSET As UInt32 = &H8000000
Private Const CFM_SUBSCRIPT As UInt32 = CFE_SUBSCRIPT Or CFE_SUPERSCRIPT
Private Const CFM_SUPERSCRIPT As UInt32 = CFM_SUBSCRIPT

Private Const CFU_UNDERLINENONE As Byte = &H0
Private Const CFU_UNDERLINE As Byte = &H1
Private Const CFU_UNDERLINEWORD As Byte = &H2
' (*) displayed as ordinary underline
Private Const CFU_UNDERLINEDOUBLE As Byte = &H3
' (*) displayed as ordinary underline
Private Const CFU_UNDERLINEDOTTED As Byte = &H4
Private Const CFU_UNDERLINEDASH As Byte = &H5
Private Const CFU_UNDERLINEDASHDOT As Byte = &H6
Private Const CFU_UNDERLINEDASHDOTDOT As Byte = &H7
Private Const CFU_UNDERLINEWAVE As Byte = &H8
Private Const CFU_UNDERLINETHICK As Byte = &H9
Private Const CFU_UNDERLINEHAIRLINE As Byte = &HA
' (*) displayed as ordinary underline

#End Region

#End Region

Public Sub New()
Me.DetectUrls = False
End Sub

<DefaultValue(False)> _
Public Shadows Property DetectUrls() As Boolean
Get
Return MyBase.DetectUrls
End Get
Set(ByVal value As Boolean)
MyBase.DetectUrls = value
End Set
End Property

Public Sub InsertLink(ByVal text As String)
InsertLink(text, Me.SelectionStart)
End Sub

Public Sub InsertLink(ByVal text As String, ByVal position As Integer)
If position < 0 OrElse position > Me.Text.Length Then
Throw New ArgumentOutOfRangeException("position")
End If

Me.SelectionStart = position
Me.SelectedText = text
Me.[Select](position, text.Length)
Me.SetSelectionLink(True)
Me.[Select](position + text.Length, 0)
End Sub

Public Sub InsertLink(ByVal text As String, ByVal hyperlink As String)
InsertLink(text, hyperlink, Me.SelectionStart)
End Sub

'Public Sub InsertLink(ByVal text As String, ByVal hyperlink As String, ByVal position As Integer)
' If position < 0 OrElse position > Me.Text.Length Then
' Throw New ArgumentOutOfRangeException("position")
' End If

' Me.SelectionStart = position
' Me.SelectedRtf = ("{\rtf1\ansi " & text & "\v #") + hyperlink & "\v0}"
' 'Me.SelectedRtf = "{\rtf1\ansi\ansicpg" & System.Text.Encoding.Default.CodePage & " " & text & "\v #" & hyperlink & "\v0}"
' Me.[Select](position, text.Length + hyperlink.Length + 1)
' Me.SetSelectionLink(True)
' Me.[Select](position + text.Length + hyperlink.Length + 1, 0)
'End Sub
Public Sub InsertLink(ByVal text As String, ByVal hyperlink As String, ByVal position As Integer)
If position < 0 OrElse position > Me.Text.Length Then
Throw New ArgumentOutOfRangeException("position")
End If

Dim startLinkStr As String = "LINKSTART"
Dim endLinkStr As String = "#LINKEND"

Dim linkStartPos As Integer = position - startLinkStr.Length

Me.SelectionStart = position
Me.SelectedRtf = ("{\rtf1\ansi \v LINKSTART\v0" & text & "\v #") + hyperlink & "#LINKEND\v0}"
Me.[Select](position, text.Length + hyperlink.Length + 1 + endLinkStr.Length + startLinkStr.Length)
Me.SetSelectionLink(True)
Me.[Select](position + text.Length + hyperlink.Length + 1, 0)
End Sub
Public Sub ShowLinks()
Dim curPos As Integer = 0

Dim startTextStr As String = "LINKSTART"
Dim endTextStr As String = "#"
Dim endLinkStr As String = "#LINKEND"

While RtfHasMoreLinks(curPos)
' Find hidden link text
Dim sPos As Integer = Me.Text.IndexOf(startTextStr, curPos)
Dim hStartIndex As Integer = sPos

sPos += startTextStr.Length
Dim ePos As Integer = Me.Text.IndexOf(endTextStr, sPos)

' Now we have the text of link
Dim linkText As String = Me.Text.Substring(sPos, (ePos - sPos))

' Get the start position of link
Dim sLinkPos As Integer = ePos + endTextStr.Length
Dim eLinkPos As Integer = Me.Text.IndexOf(endLinkStr, sPos)

' The link
Dim hLink As String = Me.Text.Substring(sLinkPos, (eLinkPos - sLinkPos))

Dim hEndIndex As Integer = eLinkPos + endLinkStr.Length

' Show the link in box
ShowDistinctLink(hStartIndex, hEndIndex, linkText, hLink)

' Save the current end post at current position
curPos = eLinkPos
End While
End Sub
Private Function RtfHasMoreLinks(ByVal curPos As Integer) As Boolean
Return (If(Me.Text.IndexOf("LINKSTART", curPos) > curPos, True, False))
End Function

Private Sub ShowDistinctLink(ByVal sPos As Integer, ByVal ePos As Integer, ByVal displayText As String, ByVal hyperlink As String)
If sPos < 0 OrElse sPos > ePos Then
Throw New ArgumentOutOfRangeException("position")
End If

Me.[Select](sPos, (ePos - sPos))
Me.SetSelectionLink(True)
Me.[Select](sPos + displayText.Length + hyperlink.Length + 1, 0)
End Sub
Public Sub SetSelectionLink(ByVal link As Boolean)
SetSelectionStyle(CFM_LINK, IIf(link, CFE_LINK, 0))
End Sub

Public Function GetSelectionLink() As Integer
Return GetSelectionStyle(CFM_LINK, CFE_LINK)
End Function

Private Sub SetSelectionStyle(ByVal mask As UInt32, ByVal effect As UInt32)
Dim cf As New CHARFORMAT2_STRUCT()
cf.cbSize = Convert.ToUInt32(Marshal.SizeOf(cf))
cf.dwMask = mask
cf.dwEffects = effect

Dim wpar As New IntPtr(SCF_SELECTION)
Dim lpar As IntPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf))
Marshal.StructureToPtr(cf, lpar, False)

Dim res As IntPtr = SendMessage(Handle, EM_SETCHARFORMAT, wpar, lpar)

Marshal.FreeCoTaskMem(lpar)
End Sub

Private Function GetSelectionStyle(ByVal mask As UInt32, ByVal effect As UInt32) As Integer
Dim cf As New CHARFORMAT2_STRUCT()
cf.cbSize = Convert.ToUInt32(Marshal.SizeOf(cf))
cf.szFaceName = New Char(31) {}

Dim wpar As New IntPtr(SCF_SELECTION)
Dim lpar As IntPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf))
Marshal.StructureToPtr(cf, lpar, False)

Dim res As IntPtr = SendMessage(Handle, EM_GETCHARFORMAT, wpar, lpar)

cf = DirectCast(Marshal.PtrToStructure(lpar, GetType(CHARFORMAT2_STRUCT)), CHARFORMAT2_STRUCT)

Dim state As Integer
If (cf.dwMask And mask) = mask Then
If (cf.dwEffects And effect) = effect Then
state = 1
Else
state = 0
End If
Else
state = -1
End If

Marshal.FreeCoTaskMem(lpar)
Return state
End Function
End Class
End Namespace

Thanks in advance

Found another strange thing, when you minimize the program to the systray all links disappear. The text is still there when you open the form, but no links.

I have no clue how to solve this, I hope someone can figure out this hard nut.
/Thanks

to test...add a notifyicon and those events:

private void notifyIcon1_Click(object sender, System.EventArgs e)
{
Show();
this.WindowState = FormWindowState.Normal;
}

private void Form1_SizeChanged(object sender, System.EventArgs e)
{
if ( this.WindowState == FormWindowState.Minimized )
{
this.ShowInTaskbar = false;
Hide();
}
else
this.ShowInTaskbar = true;
}

Hi!
Funny effect, although I don't have the slightest idea why the RTB loses the link information. Confused | :confused:

Could be that MS is trying to be smart and to save some resources when the RichEdit Control is not visible. In order to save the control state they could stream out the RichText and store it somewhere. When showing the control again they'd have to stream in the RichText and because the links don't show up in the RichText they get lost. Could be an explanation, although verifying it would require some heavy debugging...

Nevertheless, I've found a workaround:
When you set WindowState to FormWindowState.Minimized and ShowInTaskbar to false, there's no need to Hide() the window.
If you remove the calls to Hide() and Show() from your code, the behaviour will be the same and the links will remain.

Regards,
mav

Hi, this control really rocks, great work Smile | :)

I have a problem that I almost can't believe, I can't clear the textbox??

Nothing happens both with

richTextBoxEx1.Text = "";
or
richTextBoxEx1.Clear();

The bad thing is that I can't reproduce this in the demo project, but it happens in my application.

Does any one recognize this symptom or have ideas about debugging this thing, I would be greatful.

/Thanks

Hi!

That's really strange, setting the Text property or calling Clear aren't being touched and thus the original methods from the built-in RTB.

I've never ever seen a behaviour like this, so perhaps you're not clearing the correct control? I.e. you're looking at richTextBoxEx2 and are clearing richTextBoxEx1?

Set a breakpoint to one of the above calls, check richTextBoxEx1.Text before the call and after.

Good luck,
mav

Ok, at last I could reproduce the behaviour in the demo.

Everything works fine until I use any of the swedish letters åäö in the link text.
richTextBoxEx1.InsertLink("åäö", "http://www.demo.se"). Then it's impossible to remove any text in the textbox with the clear (or text) method.

The swedish letters can easily be cleared if you write them as normal text, so it should have something to do with the linktext.

I Also found a workaround for this behaviour...
richTextBoxEx1.InsertLink("a","a",0);
richTextBoxEx1.Clear();

Think i'm happy for the moment but if someone can explain this phenomenon it would be great.

/Lets rock'n roll

When getting textBox.Rtf, the links are not there. Is there anyway to add the link structure to the rtf that microsoft word does when saving a word docuement that contians links as an Rtf document.

Sorry, no way to do this easily.
The underlying RichEdit control is streaming out the RTF content and there is no trace of the links.
You could save your links separately, but then you'll have to put them in manually as well when loading.

The good news: You don't neccessarily have to use a separate file to save the link information. Inserting '\v0' and '\v' into the richtext to make parts of the document invisible works nicely (as you can see from the code), so you could put your link information invisibly at the very beginning of the document, for example.

Regards,
mav

Any tips on persisting links through a save and a reload of the rtf file? They are not maintained now.

-Jazz

I'm afraid there won't be an easy solution for this.
The link attribute is not visible in the RTF code and thus cannot be saved along with the rest of RTF.

You'd have to persist the links separately.

Regards,
mav

plz any one help me
when i save the link is lost
how i can solve this problem? Smile | :)

Hi, thx for you code.
Does anybody know how to create link on an image in a RichTextBox. The image is an EMF.

Thx.

Nicolas

dear mav,

Thanks for your beautiful program. It helped me a lot with my work.

But I have a problem using it.when there is a unicode (utf-8) character in the text after changing it to the link the characters are changed to unknown codes.

would you please help me with this problem.

Ok,

I found the solution myself.

In the InsertLink function change the following line:
this.SelectedRtf = @"{\rtf1\ansi "+text+@"\v #"+hyperlink+@"\v0}";
to this:

this.SelectedRtf = @"{\rtf1\rtlch "+text+@"\v #"+hyperlink+@"\v0}";

Thanks again

Hello

Can you reference to your solution about that.

Because i want to change the codepage to iso8859-9 (Turkish) to solve same problem Smile | :)

Thanks

Hi,
I have the same problem but when i use your solution, it isn't correct.

Can you send me your RichTextBoxEx.cs file ?

Thank for your support.

Mav do you see what is wrong with this vb.net code. It returns 0 off the sendmessage. It is in a usercontrol:

Private Structure CHARFORMAT2_STRUCT
Public cbSize As Int32
Public dwMask As Int32
Public dwEffects As Int32
Public yHeight As Int32
Public yOffset As Int32
Public crTextColor As Int32
Public bCharSet As Byte
Public bPitchAndFamily As Byte

Public szFaceName() As Char
Public wWeight As UInt16
Public sSpacing As UInt16
Public crBackColor As Integer ' Color.ToArgb() -> int
Public lcid As Integer
Public dwReserved As Integer
Public sStyle As Int16
Public wKerning As Int16
Public bUnderlineType As Byte
Public bAnimation As Byte
Public bRevAuthor As Byte
Public bReserved1 As Byte
End Structure

Private Overloads Declare Auto Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As IntPtr, _
ByVal msg As Int32, _
ByVal wParam As IntPtr, _
ByVal lParam As IntPtr) As IntPtr
'End Function

Private Const WM_USER As Integer = &H400&
Private Const EM_FORMATRANGE As Integer = WM_USER + 57
Private Const EM_GETCHARFORMAT As Integer = WM_USER + 58
Private Const EM_SETCHARFORMAT As Integer = WM_USER + 68

Private Const SCF_SELECTION As Integer = &H1&
Private Const SCF_WORD As Integer = &H2&
Private Const SCF_ALL As Integer = &H4&

#Region "CHARFORMAT2 Flags"
Private Const CFE_BOLD As Int32 = &H1&
Private Const CFE_ITALIC As Int32 = &H2&
Private Const CFE_UNDERLINE As Int32 = &H4&
Private Const CFE_STRIKEOUT As Int32 = &H8&
Private Const CFE_PROTECTED As Int32 = &H10&
Private Const CFE_LINK As Int32 = &H20&
Private Const CFE_AUTOCOLOR As Int32 = &H40000000&
Private Const CFE_SUBSCRIPT As Int32 = &H10000& 'Superscript and subscript are
Private Const CFE_SUPERSCRIPT As Int32 = &H20000& 'mutually exclusive

Private Const CFM_SMALLCAPS As Integer = &H40& ' (*)
Private Const CFM_ALLCAPS As Integer = &H80& ' Displayed by 3.0
Private Const CFM_HIDDEN As Integer = &H100& ' Hidden by 3.0
Private Const CFM_OUTLINE As Integer = &H200& ' (*)
Private Const CFM_SHADOW As Integer = &H400& ' (*)
Private Const CFM_EMBOSS As Integer = &H800& ' (*)
Private Const CFM_IMPRINT As Integer = &H1000& ' (*)
Private Const CFM_DISABLED As Integer = &H2000&
Private Const CFM_REVISED As Integer = &H4000&

Private Const CFM_BACKCOLOR As Integer = &H4000000&
Private Const CFM_LCID As Integer = &H2000000&
Private Const CFM_UNDERLINETYPE As Integer = &H800000& ' Many displayed by 3.0
Private Const CFM_WEIGHT As Integer = &H400000&
Private Const CFM_SPACING As Integer = &H200000& ' Displayed by 3.0
Private Const CFM_KERNING As Integer = &H100000& ' (*)
Private Const CFM_STYLE As Integer = &H80000& ' (*)
Private Const CFM_ANIMATION As Integer = &H40000& ' (*)
Private Const CFM_REVAUTHOR As Integer = &H8000&

Private Const CFM_BOLD As Int32 = &H1&
Private Const CFM_ITALIC As Int32 = &H2&
Private Const CFM_UNDERLINE As Int32 = &H4&
Private Const CFM_STRIKEOUT As Int32 = &H8&
Private Const CFM_PROTECTED As Int32 = &H10&
Private Const CFM_LINK As Int32 = &H20&
'Private Const CFM_SIZE As Int32 = &H80000000&
Private Const CFM_COLOR As Int32 = &H40000000&
Private Const CFM_FACE As Int32 = &H20000000&
Private Const CFM_OFFSET As Int32 = &H10000000&
Private Const CFM_CHARSET As Int32 = &H8000000&
Private Const CFM_SUBSCRIPT As Int32 = CFE_SUBSCRIPT Or CFE_SUPERSCRIPT
Private Const CFM_SUPERSCRIPT As Int32 = CFM_SUBSCRIPT

Private Const CFU_UNDERLINENONE As Byte = &H0&
Private Const CFU_UNDERLINE As Byte = &H1&
Private Const CFU_UNDERLINEWORD As Byte = &H2& ' (*) displayed as ordinary underline
Private Const CFU_UNDERLINEDOUBLE As Byte = &H3& ' (*) displayed as ordinary underline
Private Const CFU_UNDERLINEDOTTED As Byte = &H4&
Private Const CFU_UNDERLINEDASH As Byte = &H5&
Private Const CFU_UNDERLINEDASHDOT As Byte = &H6&
Private Const CFU_UNDERLINEDASHDOTDOT As Byte = &H7&
Private Const CFU_UNDERLINEWAVE As Byte = &H8&
Private Const CFU_UNDERLINETHICK As Byte = &H9&
Private Const CFU_UNDERLINEHAIRLINE As Byte = &HA& ' (*) displayed as ordinary underline
#End Region

#End Region

#Region " Methods "

'/
'/ Insert a given text as a link into the RichTextBox at the current insert position.
'/
'/ Text to be inserted
Public Overloads Sub InsertLink(ByVal [text] As String)
InsertLink([text], Me.RichTextBox.SelectionStart)
End Sub

'/
'/ Insert a given text at a given position as a link.
'/
'/ Text to be inserted
'/ Insert position
Public Overloads Sub InsertLink(ByVal [text] As String, ByVal position As Integer)
If position < 0 OrElse position > Me.Text.Length Then
Throw New ArgumentOutOfRangeException("position")
End If
Me.RichTextBox.SelectionStart = position
Me.RichTextBox.SelectedText = [text]
Me.RichTextBox.Select(position, [text].Length)
Me.SetSelectionLink(True)
Me.RichTextBox.Select(position + [text].Length, 0)
End Sub

'/
'/ Insert a given text at at the current input position as a link.
'/ The link text is followed by a hash (#) and the given hyperlink text, both of
'/ them invisible.
'/ When clicked on, the whole link text and hyperlink string are given in the
'/ LinkClickedEventArgs.
'/
'/ Text to be inserted
'/ Invisible hyperlink string to be inserted
Public Overloads Sub InsertLink(ByVal [text] As String, ByVal hyperlink As String)
InsertLink([text], hyperlink, Me.RichTextBox.SelectionStart)
End Sub

'/
'/ Insert a given text at a given position as a link. The link text is followed by
'/ a hash (#) and the given hyperlink text, both of them invisible.
'/ When clicked on, the whole link text and hyperlink string are given in the
'/ LinkClickedEventArgs.
'/
'/ Text to be inserted
'/ Invisible hyperlink string to be inserted
'/ Insert position
Public Overloads Sub InsertLink(ByVal [text] As String, ByVal hyperlink As String, ByVal position As Integer)
If position < 0 OrElse position > Me.Text.Length Then
Throw New ArgumentOutOfRangeException("position")
End If
Me.RichTextBox.SelectionStart = position
Me.RichTextBox.SelectedRtf = "{\rtf1\ansi " + [text] + "\v #" + hyperlink + "\v0}"
Me.RichTextBox.Select(position, [text].Length + hyperlink.Length + 1)
Me.SetSelectionLink(True)
Me.RichTextBox.Select(position + [text].Length + hyperlink.Length + 1, 0)
End Sub

'/
'/ Set the current selection's link style
'/
'/ true: set link style, false: clear link style
Public Sub SetSelectionLink(ByVal link As Boolean)
SetSelectionStyle(CFM_LINK, IIf(link, CFE_LINK, 0))
End Sub

'/
'/ Get the link style for the current selection
'/
'/ 0: link style not set, 1: link style set, -1: mixed
Public Function GetSelectionLink() As Integer
Return GetSelectionStyle(CFM_LINK, CFE_LINK)
End Function

Private Sub SetSelectionStyle(ByVal mask As Int32, ByVal effect As Int32)
Dim cf As New CHARFORMAT2_STRUCT
cf.cbSize = CType(Marshal.SizeOf(cf), Int32)
cf.dwMask = mask
cf.dwEffects = effect

Dim wpar As New IntPtr(SCF_SELECTION)
Dim lpar As IntPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf))
Marshal.StructureToPtr(cf, lpar, False)

Dim res As IntPtr = SendMessage(Me.RichTextBox.Handle, EM_SETCHARFORMAT, wpar, lpar)

Marshal.FreeCoTaskMem(lpar)
End Sub

Private Function GetSelectionStyle(ByVal mask As Int32, ByVal effect As Int32) As Integer
Dim cf As New CHARFORMAT2_STRUCT
cf.cbSize = CType(Marshal.SizeOf(cf), Int32)
cf.szFaceName = New Char(32) {}

Dim wpar As New IntPtr(SCF_SELECTION)
Dim lpar As IntPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf))
Marshal.StructureToPtr(cf, lpar, False)

Dim res As IntPtr = SendMessage(Me.RichTextBox.Handle, EM_GETCHARFORMAT, wpar, lpar)

cf = CType(Marshal.PtrToStructure(lpar, GetType(CHARFORMAT2_STRUCT)), CHARFORMAT2_STRUCT)

Dim state As Integer

' dwMask holds the information which properties are consistent throughout the selection:
If (cf.dwMask And mask) = mask Then
If (cf.dwEffects And effect) = effect Then
state = 1
Else
state = 0
End If
Else
state = -1
End If

Marshal.FreeCoTaskMem(lpar)
Return state
End Function
#End Region

Hi All,

While I was fooling around with this great extension I stumbled across a painting issue. I took the example application and simply added a button to it. I then set the tab order so that the button would have focus when the form loaded. Finally, I added some code to the linkclicked event to open a form with showdialog.

When I run the code and then click on a link (without clicking on anything else) my new form appears. The painting problem occurs if I move the new form around. The RTB control will not repaint until I close the new form. I can also get this to occur if I click on the button (to give it focus) and then click directly on a link.

Has anybody else seen this? I am pretty new with this type of API programming.

Any help is appreciated,

Al

Links with arbitrary text in a RichTextBox

Introduction

Background

How the RichEdit control manages style changes

Wrapping up the structs and messages

Using the class

Caveats

Possible extensions

Modification History

License

Comments and Discussions