EventArgs data usage RRS feed

  • Question

  • I have three classes, the FileManagerClass contains two events which are EventHandler<FileTransferEventArgs> FileMove;, and EventHandler<FileTransferEventArgs> FileMoveError;. I then have a custom EventArgs class named FileTransferEventArg that inherits from the base EventArgs class. I then have a third class called FolderDirectoryModel that then listens for the events to be raised and responds to it with either a OnFileMove(object sender, FileTransferEventArg arg) or OnFileMoveError(object sender, FileTransferEventArg arg). My problem is that I would like to use the properties inside my FileTransferEventArgs class to display the file name that was moved and if it was successful or not detailing a reason that will be inside the message property. However when I get every thing wired up im not able to view the data that is passed along. I am not sure if i am improperly using the events or I am trying to do something that is not possible.

    class FileTransferManager { public event EventHandler<FileTransferEventArgs> FileMove; public event EventHandler<FileTransferEventArgs> FileMoveError; } public class FileTransferEventArgs : EventArgs { string FileName { get; set; } string Message { get; set; } internal FileTransferEventArgs(FileModel file, string message) { this.FileName = file.FileName; this.Message = message; } } public class FolderDirectoryModel { void TransferFile(FileModel toBeTransfered, string destinationPath) { if (!File.Exists(toBeTransfered.FilePath)) { File.Move(toBeTransfered.FilePath, destinationPath); FileTransferEvents.FileTransferManager TransferAgent = new FileTransferEvents.FileTransferManager(); TransferAgent.FileMove += new EventHandler<FileTransferEventArgs>(OnFileMove); } else { FileTransferEvents.FileTransferManager TransferAgent = new FileTransferEvents.FileTransferManager(); TransferAgent.FileMoveError += new EventHandler<FileTransferEventArgs>(OnFileMoveError); } } //Handler Methods private void OnFileMoveError(object sender, FileTransferEventArgs args) { //what i want to happen

    MessageBox.Show($"File {args.FileName} has not been moved succefully to {args.FilePath} because of...."); } private void OnFileMove(object sender, FileTransferEventArgs args) {

    //what i want to happen

    MessageBox.Show($"File {args.FileName} has been moved successfully to {args.FilePath} } }


    • Edited by Rechtfertigung Saturday, June 20, 2020 1:47 PM fixed variable names and added )
    Saturday, June 20, 2020 1:43 PM


  • Hello,

    Here is a basic example.

    public class DelegatesModule
        public delegate void MonitorHandler(MonitorArgs args);


    public class MonitorArgs : EventArgs
        protected string _text;
        protected int _value;
        public MonitorArgs(string text, int value)
            _text = text;
            _value = value;
        public string Text => _text;
        public int Value => _value;

    Then in a class

    public class Operations
        public event MonitorHandler OnMonitor;

    In a method of the class above

    public async Task<int> Run(int value, System.Threading.CancellationToken token)
        var currentIndex = 0;
        while (currentIndex <= value -1)
            OnMonitor?.Invoke(new MonitorArgs("Working", currentIndex));
            currentIndex += 1;
            await Task.Delay(1, token);
            if (token.IsCancellationRequested) token.ThrowIfCancellationRequested();
        OnMonitor?.Invoke(new MonitorArgs("Done", currentIndex));
        return currentIndex;

    Here we subscribe to the event

    var ops = new Operations();
    ops.OnMonitor += OnMonitor;

    Here a progressbar uses Value from MonitorArgs and Text is used one the operation is done.

    private void OnMonitor(MonitorArgs args)
        progressBar1.Value = args.Value;
        if (args.Value == _totalIterations)

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    • Edited by KareninstructorMVP Sunday, June 21, 2020 1:39 AM bolded code
    • Proposed as answer by Naomi N Sunday, June 21, 2020 12:46 PM
    • Marked as answer by Rechtfertigung Sunday, June 21, 2020 2:14 PM
    Sunday, June 21, 2020 1:38 AM