how to read and wtrite the xls and xlsx files on the qt?are there any libs that could support these formats of files

nicker player

@SGaist
the libs u just mentioned only support the xlsx format,but not for the xls format.I just want to use the qt to transform the xls file into the xlsx file.

jsulm

@nicker-player Qt itself has no libraries to read/write Microsoft Office formats. You will need to search for third party libs.

nicker player

@jsulm
I knew that.I just wondered if anyone could offer me some useful advices.cause it is hard to find the useful libs.

JonB · 3 Oct 2025, 08:25

@nicker-player
You asked this question in 2022 at https://forum.qt.io/topic/139394/how-to-read-write-the-files-with-the-ole-format-like-xls-xlsx-doc. Did you investigate the 3rd party .xls format readers listed at https://wiki.qt.io/Handling_Microsoft_Excel_file_format? I can't imagine there will be anything more up-to-date than that.

One possibility, possibly your best while I think of it, would be to use Excel Automation to read in from .xls file and save back with .xlsx format? So Excel does the conversion for you. Some samples are in https://stackoverflow.com/questions/9918646/how-to-convert-xls-to-xlsx.

There are also a few xls to xlsx converters online, some claiming to be free. No idea how good they are.

nicker player

@JonB
thanks a lot.the topic u just mentioned is very useful.thanks a lot.

SimonSchroeder

I believe you can use OpenOffice/LibreOffice as a library. However, I personally never wanted to have such a huge library in my project.

nicker player

@SimonSchroeder
I agreed that.and in fact its too hard for me to compile the libs into my project. it is too hard.I just want a lib could trans the xls into the xlsx file.but the topics above is too complex for me.

JonB

@nicker-player
I looked years ago at using OpenOffice/LibreOffice as a library, and it is way too large and complicated.

Since we seem to have established there is no "lib" already written to translate between the formats, by now you could have used the Qt ActiveX integration to do the necessary loading and saving to convert.

nicker player

@JonB
Ive tried what u just mentioned.but it failed caused I call these codes before the qApp was inited.
some one said that I should do something before new the QAxObject.I dont know what should do to fix it.

HRESULT r = OleInitialize(0);
 if (r != S_OK && r != S_FALSE){...}
QAxObject* excel = new QAxObject();
t_ctrl_state = excel->setControl("Excel.Application");

it occured that:
CoCreateInstance failure
QAxBase::setControl: requested control Excel.Application could not be instantiated

jsulm

@nicker-player said in how to read and wtrite the xls and xlsx files on the qt?are there any libs that could support these formats of files:

but it failed caused I call these codes before the qApp was inited

Then do it after QApplication initialization.
QAxObject is a QObject and QObjects require QApplication instance.

nicker player

but if that.what should i do to call this in a std:: thread .dose the qloop would fail?

jsulm

@nicker-player Sorry, I don't know what you mean. Why do you need a thread?

ChrisW67

@nicker-player said in how to read and wtrite the xls and xlsx files on the qt?are there any libs that could support these formats of files:

QAxBase::setControl: requested control Excel.Application could not be instantiated

Is Excel installed on the machine you are running this on?