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Hyperlink to a line of RichTextBox in C#

I am looking a way to create a HyperLink in a RichTextBox pointing to a line of the text of the same RichTextBox.
I just found how to do that with Internet Links but I don't find a way to do it with the same text inside of the control (It's like Hyperlinks in MS Word pointing to a header or bookmark).
Thanks in Advance. - CCB

No, this will not work unless you code the necessary stuff yourself.
Two suggestions:
A simple workaround with links always starting with www.
The nicer solution with arbitrary link text
Let's have a look at both options..:
Using the built-in functionality of recognizing an URL seems the right way to start, but the link will always have to look like a URL, not like a hyperlink to an anchor.. If you can live with a solution that has, say, links like this: www.goto.234 and anchors like this: #234# this is really rather simple..
A working example can be as simple as this:
private void richTextBox1_LinkClicked(object sender, LinkClickedEventArgs e)
{
var s = e.LinkText.Split('.');
string anchor = s[2];
int a = richTextBox1.Text.IndexOf("#" + anchor + "#" );
if (a >= 0) richTextBox1.SelectionStart = a; else return; // do add more checks!
richTextBox1.SelectionLength = 0;
Text = anchor + " # " + a;
//richTextBox1.ScrollToCaret(); <<--- this crashes on my machine!
// so I take the jump out of the click event and it works:
Timer ttt = new Timer() { Interval = 100 };
ttt.Tick += (ss, ee) => { richTextBox1.ScrollToCaret(); ttt.Stop(); };
}
Option two: If you'd rather have more choice of how the links should read you can do this:
Start by formatting each to
Start with a special character, say a tilde '~'
format it to look blue and underlined if you want to
Either make it one word or replace space by underlines and format those to have the forecolor equal to the backcolor
Now this can do the job:
public string delimiters = " ()[]{}!&?=/\\,;.\r\n";
private void richTextBox2_Click(object sender, EventArgs e)
{
int sstart = -1;
string s = getWordAt(richTextBox2.Text,
richTextBox2.SelectionStart, delimiters, out sstart);
if (s.Length < 3) return;
string char1 = s.Substring(0, 1);
if (char1 == "~")
{
int p = richTextBox2.Text.IndexOf("#" + s.Substring(1));
if (p >= 0) { richTextBox2.SelectionStart = p; richTextBox2.ScrollToCaret(); }
}
}
public static string getWordAt(string text, int cursorPos,
string delimiters, out int selStart)
{
int startPos = 0;
selStart = startPos;
if ((cursorPos < 0) | (cursorPos > text.Length) | (text.Length == 0)) return "";
if ((text.Length > cursorPos) & (delimiters.Contains(text[cursorPos]))) return "";
int endPos = text.Length - 1;
if (cursorPos == text.Length) endPos = text.Length - 1;
else { for (int i = cursorPos; i < text.Length; i++)
{ if (delimiters.Contains(text[i])) { endPos = i - 1; break; } } }
if (cursorPos == 0) startPos = 0;
else { for (int i = cursorPos; i > 0; i--)
{ if (delimiters.Contains(text[i])) { startPos = i + 1; break; } } }
selStart = startPos;
return text.Substring(startPos, endPos - startPos + 1);
}
Here are the two versions side by side, once at the top then after clicking on a link:
Both versions work fine, although both could do with some more checks.
Note that I was too lazy to format the pseudo-links in the second example, so they show their tildes and hashes..
Not hard to write a helper function that can insert the formatting; the search will still work as it searches in the Text, not the Rtf property..

RichTextBox is finding my search terms in funny places

I'm trying to find instances of a string in a WPF RichTextBox. What I have now almost works, but it highlights the wrong section of the document.
private int curSearchLocation;
private void FindNext_Click(object sender, RoutedEventArgs e)
{
TextRange text = new TextRange(RichEditor.Document.ContentStart, RichEditor.Document.ContentEnd);
var location = text.Text.IndexOf(SearchBox.Text, curSearchLocation, StringComparison.CurrentCultureIgnoreCase);
if (location < 0)
{
location = text.Text.IndexOf(SearchBox.Text, StringComparison.CurrentCultureIgnoreCase);
}
if (location >= 0)
{
curSearchLocation = location + 1;
RichEditor.Selection.Select(text.Start.GetPositionAtOffset(location), text.Start.GetPositionAtOffset(location + SearchBox.Text.Length));
}
else
{
curSearchLocation = 0;
MessageBox.Show("Not found");
}
RichEditor.Focus();
}
This is what happens when I search for "document":
This is because GetPositionAtOffset includes non-text elements such as opening and closing tags in its offset, which is not what I want. I couldn't find a way to ignore these elements, and I also couldn't find a way to directly get a TextPointer to the text I want, which would also solve the problem.
How can I get it to highlight the correct text?

Unfortunately the TextRange.Text strips out non-text characters, so in this case the offset computed by IndexOf will be slightly too low. That is the main problem.
I tried to solve your problem and found working solution that works fine even when we have formatted text in many paragraphs.
A lot of help is taken from this CodeProject Article. So also read that article.
int curSearchLocation;
private void FindNext_Click(object sender, RoutedEventArgs e)
{
TextRange text = new TextRange(RichEditor.Document.ContentStart, RichEditor.Document.ContentEnd);
var location = text.Text.IndexOf(SearchBox.Text, curSearchLocation, StringComparison.CurrentCultureIgnoreCase);
if (location < 0)
{
location = text.Text.IndexOf(SearchBox.Text, StringComparison.CurrentCultureIgnoreCase);
}
if (location >= 0)
{
curSearchLocation = location + 1;
Select(location, SearchBox.Text.Length);
}
else
{
curSearchLocation = 0;
MessageBox.Show("Not found");
}
RichEditor.Focus();
}
public void Select(int start, int length)
{
TextPointer tp = RichEditor.Document.ContentStart;
TextPointer tpLeft = GetPositionAtOffset(tp, start, LogicalDirection.Forward);
TextPointer tpRight = GetPositionAtOffset(tp, start + length, LogicalDirection.Forward);
RichEditor.Selection.Select(tpLeft, tpRight);
}
private TextPointer GetPositionAtOffset(TextPointer startingPoint, int offset, LogicalDirection direction)
{
TextPointer binarySearchPoint1 = null;
TextPointer binarySearchPoint2 = null;
// setup arguments appropriately
if (direction == LogicalDirection.Forward)
{
binarySearchPoint2 = this.RichEditor.Document.ContentEnd;
if (offset < 0)
{
offset = Math.Abs(offset);
}
}
if (direction == LogicalDirection.Backward)
{
binarySearchPoint2 = this.RichEditor.Document.ContentStart;
if (offset > 0)
{
offset = -offset;
}
}
// setup for binary search
bool isFound = false;
TextPointer resultTextPointer = null;
int offset2 = Math.Abs(GetOffsetInTextLength(startingPoint, binarySearchPoint2));
int halfOffset = direction == LogicalDirection.Backward ? -(offset2 / 2) : offset2 / 2;
binarySearchPoint1 = startingPoint.GetPositionAtOffset(halfOffset, direction);
int offset1 = Math.Abs(GetOffsetInTextLength(startingPoint, binarySearchPoint1));
// binary search loop
while (isFound == false)
{
if (Math.Abs(offset1) == Math.Abs(offset))
{
isFound = true;
resultTextPointer = binarySearchPoint1;
}
else
if (Math.Abs(offset2) == Math.Abs(offset))
{
isFound = true;
resultTextPointer = binarySearchPoint2;
}
else
{
if (Math.Abs(offset) < Math.Abs(offset1))
{
// this is simple case when we search in the 1st half
binarySearchPoint2 = binarySearchPoint1;
offset2 = offset1;
halfOffset = direction == LogicalDirection.Backward ? -(offset2 / 2) : offset2 / 2;
binarySearchPoint1 = startingPoint.GetPositionAtOffset(halfOffset, direction);
offset1 = Math.Abs(GetOffsetInTextLength(startingPoint, binarySearchPoint1));
}
else
{
// this is more complex case when we search in the 2nd half
int rtfOffset1 = startingPoint.GetOffsetToPosition(binarySearchPoint1);
int rtfOffset2 = startingPoint.GetOffsetToPosition(binarySearchPoint2);
int rtfOffsetMiddle = (Math.Abs(rtfOffset1) + Math.Abs(rtfOffset2)) / 2;
if (direction == LogicalDirection.Backward)
{
rtfOffsetMiddle = -rtfOffsetMiddle;
}
TextPointer binarySearchPointMiddle = startingPoint.GetPositionAtOffset(rtfOffsetMiddle, direction);
int offsetMiddle = GetOffsetInTextLength(startingPoint, binarySearchPointMiddle);
// two cases possible
if (Math.Abs(offset) < Math.Abs(offsetMiddle))
{
// 3rd quarter of search domain
binarySearchPoint2 = binarySearchPointMiddle;
offset2 = offsetMiddle;
}
else
{
// 4th quarter of the search domain
binarySearchPoint1 = binarySearchPointMiddle;
offset1 = offsetMiddle;
}
}
}
}
return resultTextPointer;
}
int GetOffsetInTextLength(TextPointer pointer1, TextPointer pointer2)
{
if (pointer1 == null || pointer2 == null)
return 0;
TextRange tr = new TextRange(pointer1, pointer2);
return tr.Text.Length;
}
Hope so this code will work for your case.

Highlight parts of text in FlowDocument

I want to highlight some parts of text in a FlowDocument based on the search results. What I am doing is getting the indexes where the searched word occures in the text of the FlowDocument and then apply background color on the text range starting at the found index, ending at the found index + search word length.
TextRange content = new TextRange(myFlowDocument.ContentStart,
myFlowDocument.ContentEnd);
List<int> highlights = GetHighlights(content.Text, search);
foreach (int index in highlights)
{
var start = myFlowDocument.ContentStart;
var startPos = start.GetPositionAtOffset(index);
var endPos = start.GetPositionAtOffset(index + search.Length);
var textRange = new TextRange(startPos, endPos);
textRange.ApplyPropertyValue(TextElement.BackgroundProperty,
new SolidColorBrush(Colors.Yellow));
}
TextRange newRange = new TextRange(myFlowDocument.ContentStart,
newDocument.ContentEnd);
FlowDocument fd = (FlowDocument)XamlReader.Parse(newRange.Text);
The problem is, that I am searching indexes in the text of the document but when I'm returning the FlowDocument the xaml tags are added and I see the highlights moved.
How can I fix it?

Finaly, inspired by the answer of user007, after making some modifications I managed to highlight all the occurences of a string in a FlowDocument. Here is my code:
for (TextPointer position = newDocument.ContentStart;
position != null && position.CompareTo(newDocument.ContentEnd) <= 0;
position = position.GetNextContextPosition(LogicalDirection.Forward))
{
if (position.CompareTo(newDocument.ContentEnd) == 0)
{
return newDocument;
}
String textRun = position.GetTextInRun(LogicalDirection.Forward);
StringComparison stringComparison = StringComparison.CurrentCulture;
Int32 indexInRun = textRun.IndexOf(search, stringComparison);
if (indexInRun >= 0)
{
position = position.GetPositionAtOffset(indexInRun);
if (position != null)
{
TextPointer nextPointer = position.GetPositionAtOffset(search.Length);
TextRange textRange = new TextRange(position, nextPointer);
textRange.ApplyPropertyValue(TextElement.BackgroundProperty,
new SolidColorBrush(Colors.Yellow));
}
}
}

You need to iterate using GetNextContextPosition(LogicalDirection.Forward) and get TextPointer, use this one with previous TextPointer to construct TextRange. On this TextRange you can apply your logic.
What you can't do is use single TextRange from FlowDocument for searching text. FlowDocument is not only text:
private void Button_Click(object sender, RoutedEventArgs e)
{
String search = this.content.Text;
TextPointer text = doc.ContentStart;
while (true)
{
TextPointer next = text.GetNextContextPosition(LogicalDirection.Forward);
if (next == null)
{
break;
}
TextRange txt = new TextRange(text, next);
int indx = txt.Text.IndexOf(search);
if (indx > 0)
{
TextPointer sta = text.GetPositionAtOffset(indx);
TextPointer end = text.GetPositionAtOffset(indx + search.Length);
TextRange textR = new TextRange(sta, end);
textR.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(Colors.Yellow));
}
text = next;
}
}
UPDATE:
it does not work allways, for example if you have list, special characters (\t) are counted by IndexOf, but GetPositionAtOffset doesn't count them in:
• ListItem 1
• ListItem 2
• ListItem 3
this line:
int indx = txt.Text.IndexOf(search);
could be replaced with:
int indx = Regex.Replace(txt.Text,
"[^a-zA-Z0-9_.]+", "", RegexOptions.Compiled).IndexOf(search);

kzub's answer did not seem to work for me so I also created a solution expanding on user007 to highlight all instances of a substring in TextPointer text. It also ignores case and will highlight all matches:
public static void HighlightWords(TextPointer text, string searchWord, string stringText)
{
int instancesOfSearchKey = Regex.Matches(stringText.ToLower(), searchWord.ToLower()).Count;
for (int i = 0; i < instancesOfSearchKey; i++)
{
int lastInstanceIndex = HighlightNextInstance(text, searchWord);
if (lastInstanceIndex == -1)
{
break;
}
text = text.GetPositionAtOffset(lastInstanceIndex);
}
}
private static int HighlightNextInstance(TextPointer text, string searchWord)
{
int indexOfLastInstance = -1;
while (true)
{
TextPointer next = text.GetNextContextPosition(LogicalDirection.Forward);
if (next == null)
{
break;
}
TextRange newText = new TextRange(text, next);
int index = newText.Text.ToLower().IndexOf(searchWord.ToLower());
if (index != -1)
{
indexOfLastInstance = index;
}
if (index > 0)
{
TextPointer start = text.GetPositionAtOffset(index);
TextPointer end = text.GetPositionAtOffset(index + searchWord.Length);
TextRange textRange = new TextRange(start, end);
textRange.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(Colors.Yellow));
}
text = next;
}
return indexOfLastInstance;
}

Right Positioning For Context-Hint List (Intellisense)

just like this image from Avalon:
how to do the right positioning for a context-hint or intellisense?
senario:
im working on a code-editor and i use richtextbox(rtb) as the c-editor and the combobox(lb) as the context-hint .
all codes are almost done() except for right positioning for combobox(context hint) .
i use this code:
Point cursorPt = Cursor.Position;
lb.Location = PointToClient(cursorPt);
but its appearing when mouse cursor was ... if mouse cursor was outside the form it will not appear also .
further more heres the codes:
public void TextChangedEvent(object sender, EventArgs e)
{
lb.BringToFront();
RichTextBox rtb = sender as RichTextBox;
if (rtb != null)
{
//pass through to the HighlightType class
HighlighType HighlighType = new HighlighType(rtb);
lb.Visible = false;
lb.Items.Clear();
}
// Calculate the starting position of the current line.
int start = 0, end = 0;
for (start = rtb.SelectionStart - 1; start > 0; start--)
{
if (rtb.Text[start] == '\n') { start++; break; }
}
// Calculate the end position of the current line.
for (end = rtb.SelectionStart; end < rtb.Text.Length; end++)
{
if (rtb.Text[end] == '\n') break;
}
// Extract the current line that is being edited.
String line = rtb.Text.Substring(start, end - start);
// Backup the users current selection point.
int selectionStart = rtb.SelectionStart;
int selectionLength = rtb.SelectionLength;
// Split the line into tokens.
Regex r = new Regex("([ \\t{}();])");
Regex singlequote = new Regex("\'[^\"]*\'");
Regex doublequote = new Regex("\"[^\"]*\"");
string[] tokens = r.Split(line);
int index = start;
foreach (string token in tokens)
{
// Set the token's default color and font.
rtb.SelectionStart = index;
rtb.SelectionLength = token.Length;
rtb.SelectionColor = Color.Black;
rtb.SelectionFont = new Font("Courier New", 10, FontStyle.Regular);
if (token == "//" || token.StartsWith("//"))
{
// Find the start of the comment and then extract the whole comment.
int length = line.Length - (index - start);
string commentText = rtb.Text.Substring(index, length);
rtb.SelectionStart = index;
rtb.SelectionLength = length;
HighlighType.commentsType(rtb);
break;
}
//*** invention code:
Point cursorPt = Cursor.Position;
lb.Location = PointToClient(cursorPt);
KeyWord keywordsL = new KeyWord();
KeyWord eventsL = new KeyWord();
if (token == "." || token.StartsWith(".") & token.EndsWith(" "))
{
foreach (string str in keywordsL.keywords)
{
lb.Items.Add(str);
lb.Visible = true;
lb.Focus();
}
ty in advance!

Point point = this.rtb.GetPositionFromCharIndex(rtb.SelectionStart);
this.lb.Location = point;

How to select RichTextBox text given an index and length

If you are only given an index and length (or EndIndex) of a certain text to select, how do you perform this in WPF version of RichTextBox?
This is very doable in Textbox as you can call Textbox.Select(startIndex,Length) but I don't see anything equivalent in RTB.
Edit: I have found the answer to making a selection
internal string Select(RichTextBox rtb, int index, int length)
{
TextRange textRange = new TextRange(rtb.Document.ContentStart, rtb.Document.ContentEnd);
if (textRange.Text.Length >= (index + length))
{
TextPointer start = textRange.Start.GetPositionAtOffset(index, LogicalDirection.Forward);
TextPointer end = textRange.Start.GetPositionAtOffset(index + length, LogicalDirection.Backward);
rtb.Selection.Select(start, end);
}
return rtb.Selection.Text;
}
However, when I try to highlight the line after the selection has been made:
rtb.Selection.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(Colors.LightBlue));
The highlighting feature works only on the first try and breaks after second try. Anyone know the reason for this?

Ok this question is old but i finally found the Answer so i put this here.
I was having similiar issues when i tried to make some Syntaxhighlighter using the RichTextBox.
What I found out is, that when you play arround with ApplyPropertyValue you cannot simply use GetPositionAtOffset anymore. I believe that applying propertyvalues seems to change the "internal positions" of TextTokens inside the Document, hence 'braking' this functionality.
The Workaround:
Everytime you need to work with GetPositionAtOffset first call ClearAllProperties on the complete TextRange of the Document, then reapply all your properties using ApplyPropertyValue but thistime from right to left. (right means highest offset)
I dont know if you had applied any PropertyValues expect the Selection highlighting, so you might need to put more thinking inthere.
This is how my code looked when it caused the Problem:
private void _highlightTokens(FlowDocument document)
{
TextRange fullRange = new TextRange(document.ContentStart, document.ContentEnd);
foreach (Token token in _tokenizer.GetTokens(fullRange.Text))
{
TextPointer start = fullRange.Start.GetPositionAtOffset(token.Position);
TextPointer end = start.GetPositionAtOffset(token.Length);
TextRange range = new TextRange(start, end);
range.ApplyPropertyValue(TextElement.ForegroundProperty, _getTokenColor(token));
}
}
And i fixed it like this:
private void _highlightTokens(FlowDocument document)
{
TextRange fullRange = new TextRange(document.ContentStart, document.ContentEnd);
fullRange.ClearAllProperties(); // NOTICE: first remove allProperties.
foreach (Token token in _tokenizer.GetTokens(fullRange.Text).Reverse()) // NOTICE: Reverse() to make the "right to left" work
{
TextPointer start = fullRange.Start.GetPositionAtOffset(token.Position);
TextPointer end = start.GetPositionAtOffset(token.Length);
TextRange range = new TextRange(start, end);
range.ApplyPropertyValue(TextElement.ForegroundProperty, _getTokenColor(token));
}
}

Use the Select() method on the RichTextBox.Selection property.

Blockquote you can get the text between spaces.....
private string RichWordOver(RichTextBox rch, int x, int y)
{
int pos = rch.GetCharIndexFromPosition(new Point(x, y));
if (pos <= 0) return "";
string txt = rch.Text;
int start_pos;
for (start_pos = pos; start_pos >= 0; start_pos--)
{
char ch = txt[start_pos];
if (!char.IsLetterOrDigit(ch) && !(ch=='_')) break;
}
start_pos++;
int end_pos;
for (end_pos = pos; end_pos < txt.Length; end_pos++)
{
char ch = txt[end_pos];
if (!char.IsLetterOrDigit(ch) && !(ch == '_')) break;
}
end_pos--;
if (start_pos > end_pos) return "";
return txt.Substring(start_pos, end_pos - start_pos + 1);
}
private void rchText_MouseClick(object sender, MouseEventArgs e)
{
MessageBox.Show(RichWordOver(rchText, e.X, e.Y));
}