MATLAB: Importing files automatically callback function error

error call back need help

function importfcn
 % wait an extra second to ensure that the file modification is complete
 pause(1.0);
 % read the data from file
 fileToRead = fullfile('C:\Users\wolfgang\Desktop\file1.csv');
 circa = xlsread(fileToRead);
 kevin=0.5*(circa(:,4)+circa(:,5)).' 
assignin('base','kevin',kevin)
   % do something with the data
  end
fsw = System.IO.FileSystemWatcher();
fsw.Path = 'C:\Users\wolfgang\Desktop';
fsw.Filter = 'file.csv';
fsw.EnableRaisingEvents = true;
listenerhandle = addlistener(fsw, 'Changed', @importfcn);
%signature of importfcn is function importfcn(sender, eventargs)
%add a small delay in importfcn before reading the file as the event is raised
%to make sure that file modification is complete
Then I get the following error: Warning: Error occurred while executing callback: Error using importfcn Too many input arguments.
Warning: Error occurred while executing callback: Error using importfcn Too many input arguments.
When I type in importfcn then everything is ok and the file gets imported as variable kevin.

Best Answer

addlistener automatically passes along two inputs, source and eventdata.
You can either have your function ignore these or ignore them in the call to addlistener
@(~,~)importfcn
The two ~s deny both inputs and then call importfcn as is.
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