cs0123 - no overload for 'ProgressChanged' matches delegate 'EventHandler' in .net core

Question

I have trouble to register a progress changed event. with the above error message from the question title.

Code:

public class AudioFileSearcher
{
    public AudioFileSearcher(string searchPath, bool includeSubFolders, Views.SoundListView.SoundList parentView)
    {
        this.progress1 = new Progress<int>();
        progress1.ProgressChanged += backgroundWorker1_ProgressChanged; //<- Error Here!
    }
    // void backgroundWorker1_ProgressChanged(object sender, EventArgs e) // also not working
    void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        // Do something
    }
    public async Task FindAudioFiles(IProgress<int> progress)
    {
        foreach (string item in longItemList)
        {
            // do long operation
            if (progress != null)
            progress.Report(0);
        }
    }
}

Every single example and stack overflow question I checked states that the Issue lays in

void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)

which would correctly be

void backgroundWorker1_ProgressChanged(object sender, EventArgs e) // also not working

other questions I checked about IProgress unfortunately all have incomplete or pseudo examples which do not work for me.

score 0 · Accepted Answer · answered Apr 26 '21 at 13:15

The examples I found were all faulty. rather than this:

public class AudioFileSearcher
{
    public AudioFileSearcher(string searchPath, bool includeSubFolders, Views.SoundListView.SoundList parentView)
    {
        this.progress1 = new Progress<int>();
        progress1.ProgressChanged += backgroundWorker1_ProgressChanged; //<- Error Here!
        Task.Run(async () => await FindAudioFiles(progress1));
    }
    void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        // Do something
    }
}

try this:

public class AudioFileSearcher
{
    public AudioFileSearcher(string searchPath, bool includeSubFolders, Views.SoundListView.SoundList parentView)
    {
        this.progress1 = new Progress<int>(
        {
            backgroundWorker1_ProgressChanged();
        });
        Task.Run(async () => await FindAudioFiles(progress1));
    }
    void backgroundWorker1_ProgressChanged()
    {
        // Do something
    }
}

cs0123 - no overload for 'ProgressChanged' matches delegate 'EventHandler' in .net core

1 Answers1