3.2 自定义一个扩展的TriggerAction类

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Windows;

using System.Windows.Interactivity;

using System.Windows.Input;

using System.Reflection;

namespace WpfApp02

{

public class ExInvokeCommandAction : TriggerAction<DependencyObject>

 {

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 string CommandName

    {

        get

    {

        base.ReadPreamble();

        return this.commandName;

    }

set

    {

        if (this.CommandName != value)

        {

            base.WritePreamble();

            this.commandName = value;

            base.WritePostscript();

        }

    }

}

public ICommand Command

{

    get

    {

        return (ICommand)base.GetValue(ExInvokeCommandAction.CommandProperty);

    }

    set

    {

        base.SetValue(ExInvokeCommandAction.CommandProperty, value);

    }

}

public object CommandParameter

{

    get

    {

        return base.GetValue(ExInvokeCommandAction.CommandParameterProperty);

    }

    set

    {

        base.SetValue(ExInvokeCommandAction.CommandParameterProperty, value);

    }

}

protected override void Invoke(object parameter)

{

    if (base.AssociatedObject != null)

    {

        ICommand command = this.ResolveCommand();

        ExCommandParameter exParameter = new ExCommandParameter

        {

            Sender = base.AssociatedObject, 

            Parameter = this.GetValue(CommandParameterProperty), 

            EventArgs = parameter as EventArgs  

        };

        if (command != null && command.CanExecute(exParameter)) 

        {

            command.Execute(exParameter);

        }

    }

}

private ICommand ResolveCommand()

{

    ICommand result = null;

    if (this.Command != null)

    {

        result = this.Command; 

    }

    else

    {

        if (base.AssociatedObject != null)

        {

            Type type = base.AssociatedObject.GetType();

            PropertyInfo[] properties = type.GetProperties(BindingFlags.Instance | BindingFlags.Public);

            PropertyInfo[] array = properties;

            for (int i = 0; i < array.Length; i++)

            {

                PropertyInfo propertyInfo = array[i];

                if (typeof(ICommand).IsAssignableFrom(propertyInfo.PropertyType) 

                && string.Equals(propertyInfo.Name, this.CommandName, StringComparison.Ordinal))

                {

                    result = (ICommand)propertyInfo.GetValue(base.AssociatedObject, null);

                }

            }

        }

    }

    return result;

}

}

}