增加异步Command命令

29WxOrderWpf/Common/AsyncDelegateCommand.cs

@@ -0,0 +1,245 @@
+using System.Linq.Expressions;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Windows.Input;
+using System.Reflection.Emit;
+using System.Resources;
+using _29WxOrderWpf.Commands;
+
+
+namespace _29WxOrderWpf.Common
+{
+
+    /// <summary>
+    /// Provides an implementation of the <see cref="IAsyncCommand"/>
+    /// </summary>
+    public class AsyncDelegateCommand : DelegateCommandBase, IAsyncCommand
+    {
+        private bool _enableParallelExecution = false;
+        private bool _isExecuting = false;
+        private readonly Func<CancellationToken, Task> _executeMethod;
+        private Func<bool> _canExecuteMethod;
+        private Func<CancellationToken> _getCancellationToken = () => CancellationToken.None;
+
+        /// <summary>
+        /// Creates a new instance of <see cref="AsyncDelegateCommand"/> with the <see cref="Func{Task}"/> to invoke on execution.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{Task}"/> to invoke when <see cref="ICommand.Execute(object)"/> is called.</param>
+        public AsyncDelegateCommand(Func<Task> executeMethod)
+#if NET6_0_OR_GREATER
+            : this (c => executeMethod().WaitAsync(c), () => true)
+#else
+            : this(c => executeMethod(), () => true)
+#endif
+        {
+
+        }
+
+        /// <summary>
+        /// Creates a new instance of <see cref="AsyncDelegateCommand"/> with the <see cref="Func{Task}"/> to invoke on execution.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{CancellationToken, Task}"/> to invoke when <see cref="ICommand.Execute(object)"/> is called.</param>
+        public AsyncDelegateCommand(Func<CancellationToken, Task> executeMethod)
+            : this(executeMethod, () => true)
+        {
+
+        }
+
+        /// <summary>
+        /// Creates a new instance of <see cref="DelegateCommand"/> with the <see cref="Func{Task}"/> to invoke on execution
+        /// and a <see langword="Func" /> to query for determining if the command can execute.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{Task}"/> to invoke when <see cref="ICommand.Execute"/> is called.</param>
+        /// <param name="canExecuteMethod">The delegate to invoke when <see cref="ICommand.CanExecute"/> is called</param>
+        public AsyncDelegateCommand(Func<Task> executeMethod, Func<bool> canExecuteMethod)
+#if NET6_0_OR_GREATER
+            : this(c => executeMethod().WaitAsync(c), canExecuteMethod)
+#else
+            : this(c => executeMethod(), canExecuteMethod)
+#endif
+        {
+        }
+
+        /// <summary>
+        /// Creates a new instance of <see cref="DelegateCommand"/> with the <see cref="Func{Task}"/> to invoke on execution
+        /// and a <see langword="Func" /> to query for determining if the command can execute.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{CancellationToken, Task}"/> to invoke when <see cref="ICommand.Execute"/> is called.</param>
+        /// <param name="canExecuteMethod">The delegate to invoke when <see cref="ICommand.CanExecute"/> is called</param>
+        public AsyncDelegateCommand(Func<CancellationToken, Task> executeMethod, Func<bool> canExecuteMethod)
+            : base()
+        {
+            if (executeMethod == null || canExecuteMethod == null)
+                throw new ArgumentNullException(nameof(executeMethod), "Neither the executeMethod nor the canExecuteMethod delegates can be null");
+
+            _executeMethod = executeMethod;
+            _canExecuteMethod = canExecuteMethod;
+        }
+
+        /// <summary>
+        /// Gets the current state of the AsyncDelegateCommand
+        /// </summary>
+        public bool IsExecuting
+        {
+            get => _isExecuting;
+            private set
+            {
+                _isExecuting = value;
+				OnCanExecuteChanged();
+            }
+        }
+
+        ///<summary>
+        /// Executes the command.
+        ///</summary>
+        public async Task Execute(CancellationToken? cancellationToken = null)
+        {
+            var token = cancellationToken ?? _getCancellationToken();
+            try
+            {
+                if (!_enableParallelExecution && IsExecuting)
+                    return;
+
+                IsExecuting = true;
+                await _executeMethod(token)
+                    .ConfigureAwait(false);
+            }
+            catch 
+            {
+                throw;
+
+            }
+            finally
+            {
+                IsExecuting = false;
+            }
+        }
+
+        /// <summary>
+        /// Determines if the command can be executed.
+        /// </summary>
+        /// <returns>Returns <see langword="true"/> if the command can execute,otherwise returns <see langword="false"/>.</returns>
+        public bool CanExecute()
+        {
+            try
+            {
+                if (!_enableParallelExecution && IsExecuting)
+                    return false;
+
+                return _canExecuteMethod?.Invoke() ?? true;
+            }
+            catch (Exception ex)
+            {
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Handle the internal invocation of <see cref="ICommand.Execute(object)"/>
+        /// </summary>
+        /// <param name="parameter">Command Parameter</param>
+        protected override async void Execute(object parameter)
+        {
+            // We don't want to wrap this in a try/catch because we already handle
+            // or mean to rethrow the exception in the call with the CancellationToken.
+            var cancellationToken = _getCancellationToken();
+            await Execute(cancellationToken)
+                .ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Handle the internal invocation of <see cref="ICommand.CanExecute(object)"/>
+        /// </summary>
+        /// <param name="parameter"></param>
+        /// <returns><see langword="true"/> if the Command Can Execute, otherwise <see langword="false" /></returns>
+        protected override bool CanExecute(object parameter)
+        {
+            return CanExecute();
+        }
+
+        /// <summary>
+        /// Enables Parallel Execution of Async Tasks
+        /// </summary>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand"/>.</returns>
+        public AsyncDelegateCommand EnableParallelExecution()
+        {
+            _enableParallelExecution = true;
+            return this;
+        }
+
+        /// <summary>
+        /// Sets the <see cref="CancellationTokenSourceFactory(Func{CancellationToken})"/> based on the specified timeout.
+        /// </summary>
+        /// <param name="timeout">A specified timeout.</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand CancelAfter(TimeSpan timeout) =>
+            CancellationTokenSourceFactory(() => new CancellationTokenSource(timeout).Token);
+
+        /// <summary>
+        /// Provides a delegate callback to provide a default CancellationToken when the Command is invoked.
+        /// </summary>
+        /// <param name="factory">The default <see cref="CancellationToken"/> Factory.</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand"/>.</returns>
+        public AsyncDelegateCommand CancellationTokenSourceFactory(Func<CancellationToken> factory)
+        {
+            _getCancellationToken = factory;
+            return this;
+        }
+
+        /// <summary>
+        /// Observes a property that implements INotifyPropertyChanged, and automatically calls DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
+        /// </summary>
+        /// <typeparam name="T">The object type containing the property specified in the expression.</typeparam>
+        /// <param name="propertyExpression">The property expression. Example: ObservesProperty(() => PropertyName).</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand"/>.</returns>
+        public AsyncDelegateCommand ObservesProperty<T>(Expression<Func<T>> propertyExpression)
+        {
+            ObservesPropertyInternal(propertyExpression);
+            return this;
+        }
+
+        /// <summary>
+        /// Observes a property that is used to determine if this command can execute, and if it implements INotifyPropertyChanged it will automatically call DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
+        /// </summary>
+        /// <param name="canExecuteExpression">The property expression. Example: ObservesCanExecute(() => PropertyName).</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand"/>.</returns>
+        public AsyncDelegateCommand ObservesCanExecute(Expression<Func<bool>> canExecuteExpression)
+        {
+            _canExecuteMethod = canExecuteExpression.Compile();
+            ObservesPropertyInternal(canExecuteExpression);
+            return this;
+        }
+
+        /// <summary>
+        /// Provides the ability to connect a delegate to catch exceptions encountered by CanExecute or the Execute methods of the DelegateCommand
+        /// </summary>
+        /// <param name="catch">TThe callback when a specific exception is encountered</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand"/>.</returns>
+        public AsyncDelegateCommand Catch<TException>(Action<TException> @catch)
+            where TException : Exception
+        {
+            return this;
+        }
+
+        /// <summary>
+        /// Provides the ability to connect a delegate to catch exceptions encountered by CanExecute or the Execute methods of the DelegateCommand
+        /// </summary>
+        /// <param name="catch">The generic / default callback when an exception is encountered</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand"/>.</returns>
+        public AsyncDelegateCommand Catch(Action<Exception> @catch)
+        {
+            return this;
+        }
+
+        Task IAsyncCommand.ExecuteAsync(object parameter)
+        {
+            return Execute(_getCancellationToken());
+        }
+
+        Task IAsyncCommand.ExecuteAsync(object parameter, CancellationToken cancellationToken)
+        {
+            return Execute(cancellationToken);
+        }
+    }
+}

29WxOrderWpf/Common/AsyncDelegateCommand{T}.cs

@@ -0,0 +1,285 @@
+using System.Linq.Expressions;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Windows.Input;
+using System.Reflection.Emit;
+using System.Resources;
+using _29WxOrderWpf.Commands;
+
+namespace _29WxOrderWpf.Common
+{
+    /// <summary>
+    /// Provides an implementation of the <see cref="IAsyncCommand"/> with a generic parameter type.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    public class AsyncDelegateCommand<T> : DelegateCommandBase, IAsyncCommand
+    {
+        private bool _enableParallelExecution = false;
+        private bool _isExecuting = false;
+        private readonly Func<T, CancellationToken, Task> _executeMethod;
+        private Func<T, bool> _canExecuteMethod;
+        private Func<CancellationToken> _getCancellationToken = () => CancellationToken.None;
+
+        /// <summary>
+        /// Creates a new instance of <see cref="AsyncDelegateCommand{T}"/> with the <see cref="Func{Task}"/> to invoke on execution.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{T, Task}"/> to invoke when <see cref="ICommand.Execute(object)"/> is called.</param>
+        public AsyncDelegateCommand(Func<T, Task> executeMethod)
+#if NET6_0_OR_GREATER
+            : this((p,t) => executeMethod(p).WaitAsync(t), _ => true)
+#else
+            : this((p, t) => executeMethod(p), _ => true)
+#endif
+        {
+
+        }
+
+        /// <summary>
+        /// Creates a new instance of <see cref="AsyncDelegateCommand{T}"/> with the <see cref="Func{Task}"/> to invoke on execution.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{T, CancellationToken, Task}"/> to invoke when <see cref="ICommand.Execute(object)"/> is called.</param>
+        public AsyncDelegateCommand(Func<T, CancellationToken, Task> executeMethod)
+            : this(executeMethod, _ => true)
+        {
+
+        }
+
+        /// <summary>
+        /// Creates a new instance of <see cref="DelegateCommand"/> with the <see cref="Func{Task}"/> to invoke on execution
+        /// and a <see langword="Func" /> to query for determining if the command can execute.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{T, Task}"/> to invoke when <see cref="ICommand.Execute"/> is called.</param>
+        /// <param name="canExecuteMethod">The delegate to invoke when <see cref="ICommand.CanExecute"/> is called</param>
+        public AsyncDelegateCommand(Func<T, Task> executeMethod, Func<T, bool> canExecuteMethod)
+#if NET6_0_OR_GREATER
+            : this((p, c) => executeMethod(p).WaitAsync(c), canExecuteMethod)
+#else
+            : this((p, c) => executeMethod(p), canExecuteMethod)
+#endif
+        {
+
+        }
+
+        /// <summary>
+        /// Creates a new instance of <see cref="DelegateCommand"/> with the <see cref="Func{Task}"/> to invoke on execution
+        /// and a <see langword="Func" /> to query for determining if the command can execute.
+        /// </summary>
+        /// <param name="executeMethod">The <see cref="Func{T, CancellationToken, Task}"/> to invoke when <see cref="ICommand.Execute"/> is called.</param>
+        /// <param name="canExecuteMethod">The delegate to invoke when <see cref="ICommand.CanExecute"/> is called</param>
+        public AsyncDelegateCommand(Func<T, CancellationToken, Task> executeMethod, Func<T, bool> canExecuteMethod)
+            : base()
+        {
+            if (executeMethod == null || canExecuteMethod == null)
+                throw new ArgumentNullException(nameof(executeMethod), "Neither the executeMethod nor the canExecuteMethod delegates can be null");
+
+
+            _executeMethod = executeMethod;
+            _canExecuteMethod = canExecuteMethod;
+        }
+
+        /// <summary>
+        /// Gets the current state of the AsyncDelegateCommand
+        /// </summary>
+        public bool IsExecuting
+        {
+            get => _isExecuting;
+            private set
+            {
+                _isExecuting = value;
+                OnCanExecuteChanged();
+            }
+        }
+
+        ///<summary>
+        /// Executes the command.
+        ///</summary>
+        public async Task Execute(T parameter, CancellationToken? cancellationToken = null)
+        {
+            var token = cancellationToken ?? _getCancellationToken();
+
+            try
+            {
+                if (!_enableParallelExecution && IsExecuting)
+                    return;
+
+                IsExecuting = true;
+                await _executeMethod(parameter, token)
+                    .ConfigureAwait(false);
+            }
+            catch (Exception ex)
+            {
+                throw;
+            }
+            finally
+            {
+                IsExecuting = false;
+            }
+        }
+
+        /// <summary>
+        /// Determines if the command can be executed.
+        /// </summary>
+        /// <returns>Returns <see langword="true"/> if the command can execute,otherwise returns <see langword="false"/>.</returns>
+        public bool CanExecute(T parameter)
+        {
+            try
+            {
+                if (!_enableParallelExecution && IsExecuting)
+                    return false;
+
+                return _canExecuteMethod?.Invoke(parameter) ?? true;
+            }
+            catch (Exception ex)
+            {
+
+                throw;
+
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Handle the internal invocation of <see cref="ICommand.Execute(object)"/>
+        /// </summary>
+        /// <param name="parameter">Command Parameter</param>
+        protected override async void Execute(object parameter)
+        {
+            var cancellationToken = _getCancellationToken();
+            T parameterAsT;
+            try
+            {
+                parameterAsT = (T)parameter;
+            }
+            catch (Exception ex)
+            {
+                throw;
+            }
+
+            // If we had an exception casting the parameter to T ,
+            // we would have already returned. We want to surface any
+            // exceptions thrown by the Execute method.
+            await Execute(parameterAsT, cancellationToken)
+                .ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Handle the internal invocation of <see cref="ICommand.CanExecute(object)"/>
+        /// </summary>
+        /// <param name="parameter"></param>
+        /// <returns><see langword="true"/> if the Command Can Execute, otherwise <see langword="false" /></returns>
+        protected override bool CanExecute(object parameter)
+        {
+            try
+            {
+                return CanExecute((T)parameter);
+            }
+            catch (Exception ex)
+            {
+                throw;
+            }
+        }
+
+        /// <summary>
+        /// Enables Parallel Execution of Async Tasks
+        /// </summary>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand<T> EnableParallelExecution()
+        {
+            _enableParallelExecution = true;
+            return this;
+        }
+
+        /// <summary>
+        /// Sets the <see cref="CancellationTokenSourceFactory(Func{CancellationToken})"/> based on the specified timeout.
+        /// </summary>
+        /// <param name="timeout">A specified timeout.</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand<T> CancelAfter(TimeSpan timeout) =>
+            CancellationTokenSourceFactory(() => new CancellationTokenSource(timeout).Token);
+
+        /// <summary>
+        /// Provides a delegate callback to provide a default CancellationToken when the Command is invoked.
+        /// </summary>
+        /// <param name="factory">The default <see cref="CancellationToken"/> Factory.</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand<T> CancellationTokenSourceFactory(Func<CancellationToken> factory)
+        {
+            _getCancellationToken = factory;
+            return this;
+        }
+
+        /// <summary>
+        /// Observes a property that implements INotifyPropertyChanged, and automatically calls DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
+        /// </summary>
+        /// <typeparam name="TType">The type of the return value of the method that this delegate encapsulates</typeparam>
+        /// <param name="propertyExpression">The property expression. Example: ObservesProperty(() => PropertyName).</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand<T> ObservesProperty<TType>(Expression<Func<TType>> propertyExpression)
+        {
+            ObservesPropertyInternal(propertyExpression);
+            return this;
+        }
+
+        /// <summary>
+        /// Observes a property that is used to determine if this command can execute, and if it implements INotifyPropertyChanged it will automatically call DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
+        /// </summary>
+        /// <param name="canExecuteExpression">The property expression. Example: ObservesCanExecute(() => PropertyName).</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand<T> ObservesCanExecute(Expression<Func<bool>> canExecuteExpression)
+        {
+            Expression<Func<T, bool>> expression = Expression.Lambda<Func<T, bool>>(canExecuteExpression.Body, Expression.Parameter(typeof(T), "o"));
+            _canExecuteMethod = expression.Compile();
+            ObservesPropertyInternal(canExecuteExpression);
+            return this;
+        }
+
+        /// <summary>
+        /// Provides the ability to connect a delegate to catch exceptions encountered by CanExecute or the Execute methods of the DelegateCommand
+        /// </summary>
+        /// <param name="catch">TThe callback when a specific exception is encountered</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand<T> Catch<TException>(Action<TException> @catch)
+            where TException : Exception
+        {
+            return this;
+        }
+
+        /// <summary>
+        /// Provides the ability to connect a delegate to catch exceptions encountered by CanExecute or the Execute methods of the DelegateCommand
+        /// </summary>
+        /// <param name="catch">The generic / default callback when an exception is encountered</param>
+        /// <returns>The current instance of <see cref="AsyncDelegateCommand{T}"/>.</returns>
+        public AsyncDelegateCommand<T> Catch(Action<Exception> @catch)
+        {
+            return this;
+        }
+
+        async Task IAsyncCommand.ExecuteAsync(object parameter)
+        {
+            try
+            {
+                // If T is not nullable this may throw an exception
+                await Execute((T)parameter, _getCancellationToken());
+            }
+            catch (Exception ex)
+            {
+                throw;
+
+            }
+        }
+
+        async Task IAsyncCommand.ExecuteAsync(object parameter, CancellationToken cancellationToken)
+        {
+            try
+            {
+                // If T is not nullable this may throw an exception
+                await Execute((T)parameter, cancellationToken);
+            }
+            catch (Exception ex)
+            {
+                throw;
+            }
+        }
+    }
+}

29WxOrderWpf/Common/IAsyncCommand.cs

@@ -0,0 +1,28 @@
+using System.Threading;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+namespace _29WxOrderWpf.Common
+{
+
+    /// <summary>
+    /// Provides an abstraction layer for custom controls which want to make use of Async Commands
+    /// </summary>
+    public interface IAsyncCommand : ICommand
+    {
+        /// <summary>
+        /// Executes the Command with a specified parameter and the Default <see cref="CancellationToken"/>.
+        /// </summary>
+        /// <param name="parameter">The Command Parameter</param>
+        /// <returns>An Asynchronous Task</returns>
+        Task ExecuteAsync(object parameter);
+
+        /// <summary>
+        /// Executes the Command with a specified parameter and using a <see cref="CancellationToken"/>
+        /// </summary>
+        /// <param name="parameter">The Command Parameter</param>
+        /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
+        /// <returns>An Asynchronous Task</returns>
+        Task ExecuteAsync(object parameter, CancellationToken cancellationToken);
+    }
+}