.NET System.IO.FileSystemWatcher callback fails in compiled matlab code

Question

Matthew Reaves 2017-1-18

2
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/320987-net-system-io-filesystemwatcher-callback-fails-in-compiled-matlab-code

评论： Jan 2017-8-22

I am running into an issue where System.IO.FileSystemWatcher appears to work when run in MATLAB but not when my MATLAB code is compiled into an executable. I've simplified my code to show an illustrative example. For simplification, assume that my object "app" only has a member property "textWatcher" which is of type System.IO.FileSystemWatcher. When I call the app constructor, I do the following:

            % Check to make sure that any .NET commands are seen
            disp('Is .NET Supported?:')
            NET.isNETSupported
            % Setup FileSystemWatcher
            app.textWatcher = System.IO.FileSystemWatcher('C:\Users\reavemt1\Documents\drs');
            app.textWatcher.Filter = 'CallbackTest.txt';
            app.textWatcher.EnableRaisingEvents = true;
            addlistener(app.textWatcher,'Changed',@(src,evnt)disp('textWatcher Callback Hit!'));
            % Display the watcher object
            app.textWatcher
            % Check the class of the created object
            class(app.textWatcher)

I'm using a diary so I can check that the print commands. As expected, here are the diary results from these lines of code:

Is .NET Supported?:
ans =
       1
ans = 
    FileSystemWatcher with properties:
               NotifyFilter: FileName, DirectoryName, LastWrite
        EnableRaisingEvents: 1
                     Filter: [1x1 System.String]
      IncludeSubdirectories: 0
         InternalBufferSize: 8192
                       Path: [1x1 System.String]
                       Site: []
        SynchronizingObject: []
                  Container: []
ans =
System.IO.FileSystemWatcher

So it appears that the object was created successfully. However, when I change the file that the FileSystemWatcher is monitoring, the program crashes immediately without executing the callback function. When this same code is run in MATLAB, the program works fine, and when the file is changed, the text "textWatcher Callback Hit!" is printed as expected.

What do I need to add to my compiled project to make this work, or is there something more sinister lurking?