Write to an already opened Excel file

The following MATLAB code works well for writing

eActiveSheetRange.Value

to the range

eActiveSheetRange

However, I have to keep the respective Excel file not opened by any application to make the writing process successful.

So, is there any way to keep the Excel file opened by, for example, Excel while making the MATLAB able to write to it without throwing errors and watch the new values be written?

excel = actxserver('Excel.Application');
wbooks = excel.Workbooks;
eWorkbook = wbooks.Open('C:\Users\Diaa\Desktop\test.xlsx');
eSheets = excel.ActiveWorkBook.Sheets;
sheet1 = eSheets.get('Item',1);
sheet1.Activate
eActiveSheetRange = get(excel.Activesheet,'Range','B1');
eActiveSheetRange.Value = 15;
eWorkbook.Save
excel.Quit
excel.delete

Edit 1

Following @J. Alex Lee's answer, I get this error

when running the following code while the file is opened by Excel at the same time:

FileName = 'C:\Users\Diaa\Desktop\test.xlsx';
SheetName = 'Sheet1';
SheetNum = find( sheetnames(FileName) == SheetName);
try
    excel = actxserver('Excel.Application');
catch
    excel = actxGetRunningServer('Excel.Application');
end
excel.Workbooks.Open(FileName).Sheets.Item(SheetNum).Activate
excel.Activesheet.Range('B1').Value = 88;
excel.Activeworkbook.Save
excel.Quit
excel.delete

Answer 1

[J. Alex Lee]

If Excel is already running by the time you want to run this with the target file open, you can't just start a new excel instance and open that workbook; it will just create a new file with the same name, and when it comes time to save, you will get the error that the file is already open (anyway that's where I encountered error when I ran your example).

Instead, you need to fetch the open Excel instance

Excel = actxGetRunningServer('Excel.Application')

If you have multiple workbooks open in the excel instance, you'll need to find the one that you want within the list Workbooks.Item

Excel.Workbooks.Item(k).FullName

Such as by looping through and checking its FullName (full path, I think)

[J. Alex Lee]

https://www.mathworks.com/help/matlab/matlab_external/example-reading-excel-spreadsheet-data.html

[Diaa]

Kindly, check my question edit about the error I receive recently.

Also, thanks for the link.

[J. Alex Lee]

So don't "Open" the workbook, if it already open in your excel app, you need to "point to it" using the Workbooks.Item property

[Emmanuel J Rodriguez]

Here is another example where you can read/write to an open MS Excel file:

https://www.mathworks.com/matlabcentral/answers/1695645-read-and-write-data-to-an-open-excel-file#comment_2125875