Binding Commands

imagecatalog/Commands/AsyncCommand.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+namespace ImageCatalog_2.Commands
+{
+    public class AsyncCommand : ICommand
+    {
+        private readonly Func<Task> _execute;
+        private readonly Func<bool> _canExecute;
+        private bool _isExecuting;
+
+        public event EventHandler CanExecuteChanged;
+
+        public AsyncCommand(Func<Task> execute, Func<bool> canExecute = null)
+        {
+            _execute = execute ?? throw new ArgumentNullException(nameof(execute));
+            _canExecute = canExecute;
+        }
+
+        public bool CanExecute(object parameter)
+        {
+            return (_canExecute?.Invoke() ?? true) && !_isExecuting;
+        }
+
+        public async void Execute(object parameter)
+        {
+            if (CanExecute(parameter))
+            {
+                try
+                {
+                    _isExecuting = true;
+                    RaiseCanExecuteChanged();
+                    await _execute();
+                }
+                finally
+                {
+                    _isExecuting = false;
+                    RaiseCanExecuteChanged();
+                }
+            }
+        }
+
+        public void RaiseCanExecuteChanged()
+        {
+            CanExecuteChanged?.Invoke(this, EventArgs.Empty);
+        }
+    }
+}