TriggerAction扩展----ExInvokeCommandAction

  Wp&Win8中使用命令绑定时，除了Button控件自带命令绑定，其他的时候是用Interactivity库中的InvokeCommandAction实现的(Win8 需要额外安装第三方NuGet包才可使用，我的MVFM示例博客中带有这个库),但使用过程中发现InvokeCommandAction并不能满足我们的要求，主要有以下几点：

  1 无法获取发送者；

  2 用EventTrigger触发时往往需要用到EventArg参数，但是InvokeCommandAction无法获取；

  3 有时需要传递多个参数，无法满足；

  于是我对InvokeCommandAction进行了一些改进，首先定义参数的结构体：

    /// <summary>      /// 扩展CommandParameter，使CommandParameter可以带事件参数      /// </summary>      public class ExCommandParameter    {        /// <summary>          /// 事件触发源          /// </summary>          public object Sender { get; set; }        /// <summary>          /// 事件参数          /// </summary>          public object EventArgs { get; set; }        /// <summary>          /// 参数          /// </summary>          public object Parameter { get; set; }        /// <summary>          /// 扩展参数          /// </summary>          public object Parameter2 { get; set; }        /// <summary>          /// 扩展参数          /// </summary>          public object Parameter3 { get; set; }    }  

  然后定义处理的TriggerAction：

 /// <summary>      /// 扩展的InvokeCommandAction      /// </summary>      public class ExInvokeCommandAction : CustomTriggerActionBase    {        private string commandName;        public static readonly DependencyProperty CommandProperty = DependencyProperty.Register("Command", typeof(ICommand), typeof(ExInvokeCommandAction), null);        public static readonly DependencyProperty CommandParameterProperty = DependencyProperty.Register("CommandParameter", typeof(object), typeof(ExInvokeCommandAction), null);        public static readonly DependencyProperty CommandParameter2Property = DependencyProperty.Register("CommandParameter2", typeof(object), typeof(ExInvokeCommandAction), null);        public static readonly DependencyProperty CommandParameter3Property = DependencyProperty.Register("CommandParameter3", typeof(object), typeof(ExInvokeCommandAction), null);        /// <summary>          /// 获得或设置此操作应调用的命令的名称。          /// </summary>          /// <value>此操作应调用的命令的名称。</value>          /// <remarks>如果设置了此属性和 Command 属性，则此属性将被后者所取代。</remarks>          public string CommandName        {            get            {                return this.commandName;            }            set            {                if (this.commandName != value)                {                    this.commandName = value;                }            }        }           /// <summary>          /// 获取或设置此操作应调用的命令。这是依赖属性。          /// </summary>          /// <value>要执行的命令。</value>          /// <remarks>如果设置了此属性和 CommandName 属性，则此属性将优先于后者。</remarks>          public ICommand Command        {            get            {                return (ICommand)base.GetValue(ExInvokeCommandAction.CommandProperty);            }            set            {                base.SetValue(ExInvokeCommandAction.CommandProperty, value);            }        }        /// <summary>          /// 获得或设置命令参数。这是依赖属性。          /// </summary>          /// <value>命令参数。</value>          /// <remarks>这是传递给 ICommand.CanExecute 和 ICommand.Execute 的值。</remarks>          public object CommandParameter        {            get            {                return base.GetValue(ExInvokeCommandAction.CommandParameterProperty);            }            set            {                base.SetValue(ExInvokeCommandAction.CommandParameterProperty, value);            }        }        public object CommandParameter2        {            get            {                return base.GetValue(ExInvokeCommandAction.CommandParameter2Property);            }            set            {                base.SetValue(ExInvokeCommandAction.CommandParameter2Property, value);            }        }        public object CommandParameter3        {            get            {                return base.GetValue(ExInvokeCommandAction.CommandParameter3Property);            }            set            {                base.SetValue(ExInvokeCommandAction.CommandParameter3Property, value);            }        }        /// <summary>          /// 调用操作。          /// </summary>          /// <param name="parameter">操作的参数。如果操作不需要参数，则可以将参数设置为空引用。</param>          protected override void Invoke(object parameter)        {            ICommand command = this.ResolveCommand();            ExCommandParameter exParameter = new ExCommandParameter            {                Sender = this.AssociatedObject,                Parameter = GetValue(CommandParameterProperty),                Parameter2 = GetValue(CommandParameter2Property),                Parameter3 = GetValue(CommandParameter3Property),                EventArgs = parameter            };            if (command != null && command.CanExecute(exParameter))            {                command.Execute(exParameter);            }        }        //手动触发        public void TriggerCommand()        {            Invoke(null);        }        public void TriggerCommand(object CommandParameter)        {            TriggerCommand(null, CommandParameter);        }        public void TriggerCommand(object sender = null, object commandParameter = null, object commandParameter2 = null, object commandParameter3 = null)        {            this.CommandParameter = commandParameter;            this.CommandParameter2 = commandParameter2;            this.CommandParameter3 = commandParameter3;            Invoke(null);        }        protected ICommand ResolveCommand()        {            ICommand result = null;            if (this.Command != null)            {                result = this.Command;            }            else            {                foreach (PropertyInfo propertyInfo in this.AssociatedObject.GetType().GetTypeInfo().DeclaredProperties)                {                    if (typeof(ICommand).GetTypeInfo().IsAssignableFrom(propertyInfo.PropertyType.GetTypeInfo()) && string.Equals(propertyInfo.Name, this.CommandName, StringComparison.Ordinal))                    {                        result = (ICommand)propertyInfo.GetValue((object)this.AssociatedObject, (object[])null);                    }                }            }            return result;        }    }

  使用时和InvokeCommandAction是一样的：

    <i:Interaction.Triggers>        <i:EventTrigger EventName="Loaded">               <Behavior:ExInvokeCommandAction Command="{Binding Command,Source={StaticResource ViewModel}}" CommandParameter="1" CommandParameter2="2" CommandParameter3="3"/>        </i:EventTrigger>    </i:Interaction.Triggers>