C# Async task and reporting issue with IProgress

Question

see my code

private async void button2_Click(object sender, EventArgs e)
        {
            List<Task<int>> tasks = new List<Task<int>>();

            for (int i = 0; i < 5; i++)
            {
                tasks.Add(Getdata(i+1));
            }

            var result = await Task.WhenAll(tasks);
        }

        public async Task<int> Getdata(int i)
        {
            IProgress<string> progress = new Progress<string>(str =>
            {
                textBox1.Text = str;
            });

            await Task.Delay(90000);
            progress.Report("Task completed "+i.ToString());
            //return Task.FromResult(10);
            return 10;
        }

I storing multiple task into list and calling all the task in one go. I am writing text into textbox after delay completes but no text is getting printed in textbox....where i made the mistake.

Answer 1

This is a mocked up single Task but may help

using System;  
using System.Threading;  
using System.Threading.Tasks;  
using System.Windows.Forms;  
  
namespace AsyncTaskProgress2  
{  
    public partial class Form1 : Form  
    {  
        private CancellationTokenSource _cts = new CancellationTokenSource();  
  
        public Form1()  
        {  
            InitializeComponent();  
        }  
  
        private async void StartButton_Click(object sender, EventArgs e)  
        {  
            var cancelled = false;  
            if (_cts.IsCancellationRequested == true)  
            {  
                _cts.Dispose();  
                _cts = new CancellationTokenSource();  
            }  
  
  
            var progressIndicator = new Progress<int>(ReportProgress);  
              
            try  
            {  
                await AsyncMethod(progressIndicator, _cts.Token);  
            }  
            catch (OperationCanceledException)  
            {  
                StatusLabel.Text = "Cancelled";  
                cancelled = true;  
            }  
  
            if (!cancelled) return;  
              
            await Task.Delay(1000);  
            StatusLabel.Text = "Go again!";  
        }  
  
        private void CancelButton_Click(object sender, EventArgs e)  
        {  
            _cts.Cancel();  
        }  
        private static async Task AsyncMethod(IProgress<int> progress, CancellationToken ct)  
        {  
  
            for (int index = 100; index <= 120; index++)  
            {  
                //Simulate an async call that takes some time to complete  
                await Task.Delay(500, ct);  
  
                if (ct.IsCancellationRequested)  
                {  
                    ct.ThrowIfCancellationRequested();  
                }  
  
                progress?.Report(index);  
  
            }  
  
        }  
        private void ReportProgress(int value)  
        {  
            StatusLabel.Text = value.ToString();  
            TextBox1.Text = value.ToString();  
        }  
  
    }  
}