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>