开火就忘了？

Question

我在 ac# wpf mvvm 应用程序中有一个不工作的 asyncRelayCommand 我有点明白我需要一个方法来解决这个问题，但我经历的指南没有提到如何制作一个 https://johnthiriet.com/mvvm-going-async-with-async-command/ 这是我经历的指南这是我的代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.ServiceModel.Dispatcher;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using GalaSoft.MvvmLight;

namespace DataConverter.Command
{

    public interface IAsyncCommand<T> : ICommand
    {
        Task ExecuteAsync(T parameter);
        bool CanExecute(T parameter);
    }

    public class AsyncCommand<T> : IAsyncCommand<T>
    {
        public event EventHandler CanExecuteChanged;

        private bool _isExecuting;
        private readonly Func<T, Task> _execute;
        private readonly Func<T, bool> _canExecute;
        private readonly IErrorHandler _errorHandler;

        public AsyncCommand(Func<T, Task> execute, Func<T, bool> canExecute = null, IErrorHandler errorHandler = null)
        {
            _execute = execute;
            _canExecute = canExecute;
            _errorHandler = errorHandler;
        }

        public bool CanExecute(T parameter)
        {
            return !_isExecuting && (_canExecute?.Invoke(parameter) ?? true);
        }

        public async Task ExecuteAsync(T parameter)
        {
            if (CanExecute(parameter))
            {
                try
                {
                    _isExecuting = true;
                    await _execute(parameter);
                }
                finally
                {
                    _isExecuting = false;
                }
            }

            RaiseCanExecuteChanged();
        }

        public void RaiseCanExecuteChanged()
        {
            CanExecuteChanged?.Invoke(this, EventArgs.Empty);
        }

        #region Explicit implementations
        bool ICommand.CanExecute(object parameter)
        {
            return CanExecute((T)parameter);
        }

        void ICommand.Execute(object parameter)
        {
            ExecuteAsync((T)parameter).FireAndForgetSafeAsync(_errorHandler);
        }
        #endregion
    }
}

谁能告诉我如何制作一个这样它会起作用我真的不明白为什么指南没有提到它但是是的

Answer 1

真正快速的 goole 搜索：https://www.google.de/search?q=FireAndForgetSafeAsync

=> https://johnthiriet.com/removing-async-void/

public static class TaskUtilities
{

    public static async void FireAndForgetSafeAsync(this Task task, IErrorHandler handler = null)
    {
       try
       {
           await task;
       }
       catch (Exception ex)
       {
           handler?.HandleError(ex);
       }
   }
}