Finding And Replacing Text

In This Topic

It is a common requirement to search for text fragments inside text documents as well to replace such fragments with different text. In Nevron Text this can be achieved programmatically.

Finding Text

The control supports two ways to search for text fragments - iterative and exhaustive. The first approach exposes an iterator like method that allows you to loop trough all occurrences of a text fragment - for example:

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// create some dummy content NSection section = new NSection(); string text = string.Empty; for (int i = 0; i < 3; i++) { text += "The quick brown fox jumps over the lazy dog."; } NParagraph paragraph = new NParagraph(text); section.Blocks.Add(paragraph); m_RichText.Content.Sections.Clear(); m_RichText.Content.Sections.Add(section); // init find settings NFindSettings settings = new NFindSettings(); settings.FindWhat = "dog"; settings.SearchDirection = ENSearchDirection.Forward; // loop through all occurances of "dog" NRangeI textRange = NRangeI.Zero; while (m_RichText.FindNext(settings, ref textRange)) { m_RichText.EditingRoot.Selection.SelectRange(textRange); m_RichText.EditingRoot.Selection.SetHighlightFillToSelectedInlines(new NColorFill(ENNamedColor.Red)); }

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// create some dummy content
NSection section = new NSection();

string text = string.Empty;

for (int i = 0; i < 3; i++)
{
text += "The quick brown fox jumps over the lazy dog.";
}

NParagraph paragraph = new NParagraph(text);
section.Blocks.Add(paragraph);

m_RichText.Content.Sections.Clear();
m_RichText.Content.Sections.Add(section);

// init find settings
NFindSettings settings = new NFindSettings();
settings.FindWhat = "dog";
settings.SearchDirection = ENSearchDirection.Forward;

// loop through all occurances of "dog"
NRangeI textRange = NRangeI.Zero;

while (m_RichText.FindNext(settings, ref textRange))
{
m_RichText.EditingRoot.Selection.SelectRange(textRange);
m_RichText.EditingRoot.Selection.SetHighlightFillToSelectedInlines(new NColorFill(ENNamedColor.Red));
}

Searching is performed from the current caret position in the direction specified in text settings.

The following table lists the options in the find settings object:

Property	Type	Description
FindWhat	string	Gets or sets the text to search for.
SearchDirection	ENSearchDirection	Gets or sets the search direction. Available options are ENSearchDirection.Forward or ENSearchDirection.Backward.
Normalization	ENNormalization	Gets or sets the type of normalization to apply to text.
MatchCase	bool	Gets or sets whether search is case sensitive.
WholeWordsOnly	bool	Whether only whole words will be matched.

Note that the Normalization property accepts values from the ENNormalization enum the following table lists the avaialable options:

ENNormalization	Description
None	No normalization is applied.
Compatible	Use Unicode compatible normalization (NFKC). Compatibility equivalence is a weaker equivalence between characters or sequences of characters that represent the same abstract character, but may have a different visual appearance or behavior.
Canonical	Use Unicode canonical normalization (NFC). Canonical equivalence is a fundamental equivalency between characters or sequences of characters that represent the same abstract character, and when correctly displayed should always have the same visual appearance and behavior.

You can also use the FindAll method which returns a list of all ranges that contain the search string:

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// init find settings NFindSettings settings = new NFindSettings(); settings.FindWhat = "dog"; settings.SearchDirection = ENSearchDirection.Forward; // find all occurances of "dog" NList<NRangeI> textRanges = m_RichText.FindAll(settings); for (int i = 0; i < textRanges.Count; i++) { m_RichText.EditingRoot.Selection.SelectRange(textRanges[i]); m_RichText.EditingRoot.Selection.SetHighlightFillToSelectedInlines(new NColorFill(ENNamedColor.Red)); }

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// init find settings
NFindSettings settings = new NFindSettings();
settings.FindWhat = "dog";
settings.SearchDirection = ENSearchDirection.Forward;

// find all occurances of "dog"
NList<NRangeI> textRanges = m_RichText.FindAll(settings);

for (int i = 0; i < textRanges.Count; i++)
{
m_RichText.EditingRoot.Selection.SelectRange(textRanges[i]);
m_RichText.EditingRoot.Selection.SetHighlightFillToSelectedInlines(new NColorFill(ENNamedColor.Red));
}

Replacing Text

The previous code examples selected a text and then applied some filling on that text. You can use the InsertText function of the selection to replace the currently selected text with something else - for example, the following code replaces all occurrences of "dog" with "bulldog":

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// init find settings NFindSettings settings = new NFindSettings(); settings.FindWhat = "dog"; settings.SearchDirection = ENSearchDirection.Forward; // find all occurances of "dog" NRangeI textRange = NRangeI.Zero; while (m_RichText.FindNext(settings, ref textRange)) { // replace dog with cat m_RichText.EditingRoot.Selection.SelectRange(textRange); m_RichText.EditingRoot.Selection.InsertText("bulldog"); }

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// init find settings
NFindSettings settings = new NFindSettings();
settings.FindWhat = "dog";
settings.SearchDirection = ENSearchDirection.Forward;

// find all occurances of "dog"
NRangeI textRange = NRangeI.Zero;

while (m_RichText.FindNext(settings, ref textRange))
{
// replace dog with cat
m_RichText.EditingRoot.Selection.SelectRange(textRange);
m_RichText.EditingRoot.Selection.InsertText("bulldog");
}

You cannot use FindAll in this case as the word "bulldog" contains more characters than "dog". This means that once you replace the word "dog" with "bulldog" you need to shift all subsequent ranges.