I have to get all the sheet names from the excel document .
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I do not know of any direct support for this. But as modern Excel files are just ZIP files, containing XML files, you could unpack it and dig into the XML to find the names.
yes Stefan Helzle ,Is there is any function to directly convert the excel file to XML or else do we need to follow any steps for the conversion.
That's no conversion. The XLSX file is a ZIP with a different extension. It contains a folder structure und XML files.