Initial

BrightSharp/Commands/AsyncCommand.cs

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+using System;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+namespace BrightSharp.Commands
+{
+    public class AsyncCommand : ICommand
+    {
+        private readonly Func<object, Task> _execute;
+        private readonly Func<object, bool> _canExecute;
+        private Action _onComplete;
+        private Action<Exception> _onFail;
+        private bool _isExecuting;
+
+        public AsyncCommand(Func<object, Task> execute) : this(execute, o => true)
+        {
+        }
+
+        public AsyncCommand(Func<object, Task> execute, Func<object, bool> canExecute)
+        {
+            _execute = execute;
+            _canExecute = canExecute;
+        }
+
+        public AsyncCommand OnComplete(Action onComplete)
+        {
+            _onComplete = onComplete;
+            return this;
+        }
+        public AsyncCommand OnFail(Action<Exception> onFail)
+        {
+            _onFail = onFail;
+            return this;
+        }
+
+        public bool CanExecute(object parameter)
+        {
+            return !_isExecuting && _canExecute(parameter);
+        }
+
+        public event EventHandler CanExecuteChanged;
+
+        public async void Execute(object parameter)
+        {
+            _isExecuting = true;
+            OnCanExecuteChanged();
+            try
+            {
+                await _execute(parameter);
+                _onComplete?.Invoke();
+            }
+            catch (Exception ex)
+            {
+                while (ex.InnerException != null)
+                    ex = ex.InnerException;
+                _onFail?.Invoke(ex);
+            }
+            finally
+            {
+                _isExecuting = false;
+                OnCanExecuteChanged();
+            }
+        }
+
+        protected virtual void OnCanExecuteChanged()
+        {
+            CanExecuteChanged?.Invoke(this, new EventArgs());
+        }
+    }
+}