importing files automatically callback function error

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.

Answer 1

[Sean de Wolski]

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.