ControlExtensions.cs

using System;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WebToolsDataMonitor
{
    public static class ControlExtensions
    {
        // 🔥 FIXED: Explicitly await the inner task block before completing the completion source
        public static Task<T> InvokeAsync<T>(this Control control, Func<Task<T>> code)
        {
            var tcs = new TaskCompletionSource<T>();

            control.BeginInvoke((MethodInvoker)(async () =>
            {
                try
                {
                    // Unwraps the inner Task<string> generated by WebView2
                    T result = await code();
                    tcs.SetResult(result);
                }
                catch (Exception ex)
                {
                    tcs.SetException(ex);
                }
            }));

            return tcs.Task;
        }

        public static Task InvokeAsync(this Control control, Func<Task> code)
        {
            var tcs = new TaskCompletionSource<bool>();

            control.BeginInvoke((MethodInvoker)(async () =>
            {
                try
                {
                    await code();
                    tcs.SetResult(true);
                }
                catch (Exception ex)
                {
                    tcs.SetException(ex);
                }
            }));

            return tcs.Task;
        }
    }
}