Matlab OOP and Warndlg Crashing Matlab

I have recently started using OOP in Matlab. I have defined a class "ReadFile" that accepts a file name via a constructor class. The class has a dependent variable "file". The get method for the variable "file" is defined by calling an external function. The external function has some error check logic which uses "warndlg" to display error.

Here is the class:

    classdef ReadFile

    properties
    % some vars
      fileName;
    end

    properties(dependent=true)
      file;
    end

    methods
    % constructor class
      function obj=ReadFile(fileName)
         obj.fileName = fileName;
      end

    % get method for dependent
      function fileInfo=get.file(obj)
         fileInfo = ExternalFunc(obj.fileName);
      end

    end

The ExternalFunc is a file read function that displays an warning dialogue if the file cannot be opened and it outputs an empty variable in place of fileInfo.

The main script looks like this:

    read = ReadFile('myFile.txt');
    data = read.file

This creates two variables in the workspace: "read" class and "data". If I input the incorrect file name then the class as expected displays the warndlg but if I try to open the "read" class from the workspace it again reopens the warndlg and keeps on opening it over and over. I can't stop execution hence I have to terminate the Matlab session. I am trying to investigate the root cause. I suspect given that I am new to OOP in Matlab, I am missing something basic.

I would appreciate any suggestions.

Thanks! Abhay

[Geoff Hayes]

Abhay - please clarify what you mean by try to open the "read" class from the workspace it again. What are you trying to open - the read instance or the file that read references?

[abhay kaul]

Geoff,

read = ReadFile('myFile.txt');

creates a variable "read" in the workspace. Please see the screenshot (my actual class is named as ReadTMPFile instead of ReadFile in the example code above). I am trying to open this class variable/instance from workspace and this keeps on throwing the warndlg over and over. It seems that opening this instance from the workspace iteratively calls the class if there is warndlg.

If I remove warndlg from the external function and simply display error in the command window in case of a failure, opening of the "read" does not cause this issue.