How to display a file in the textBrowser

[jacek]

I need to be able to display various text files as available in Windows that is .txt .doc .pdf etc

I wouldn't call .doc or .pdf file a text file. They're binary formats and QTextBrowser won't handle them. You could try to embed ActiveX controls in your application to display non-HTML files.

ui.textBrowser->setHtml(ui.datalineEdit->text());

What does ui.datalineEdit->text() contain? You are supposed to pass HTML code to QTextBrowser::setHtml(). Maybe you wanted to use QTextBrowser::setSource() instead?

To display doc pdf inside qt i think is not possible!

It is possible, but you have to use Active Qt or some 3rd party library.