Text search and extraction in pdf file

I am working for text search and extraction from pdf using third party dll itextsharp.

I am getting the text on searching but not only that text, the whole text of that page.

I thought to use phrases or chunks so that I can get pre-and post of that text only along with it instead of whole page text. Can anyone suggest me code for phrases or anything else which I can use for it. Thanks!

My code is:

string searchText = null;

string filename = System.AppDomain.CurrentDomain.BaseDirectory;

filename = @"C:\test.pdf";

searchText = textBox.Text.ToString();

List<int> pages = new List<int>();

if (File.Exists(filename))

{

PdfReader pdfReader = new PdfReader(filename);

List<Phrase> PhraseList = new List<Phrase>();

for (int page = 1; page <= pdfReader.NumberOfPages; page++)

{

ITextExtractionStrategy strategy = SimpleTextExtractionStrategy();

string currentPageText = PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy)

if (currentPageText.Contains(searchText))

{

pages.Add(page);

textBox1.AppendText(PdfTextExtractor.GetTextFromPage(pdfReader, page));

textBox1.Text += pages.ToString();

}

}

pdfReader.Close();

}