SL4 - MVVM - DelegateCommand/Action/Interaction/Triggers概括（ICommand）

///

/// DelegateCommand

///

public class DelegateCommand : ICommand

{

private Predicate < object > canExecute;

private Action < object > method;

///

/// Occurs when changes occur that affect whether the command should execute.

///

public event EventHandler CanExecuteChanged;

///

/// Initializes a new instance of the class.

///

/// The method.

public DelegateCommand( Action < object > method)

:

this (method, null )

{

}

///

/// Initializes a new instance of the class.

///

/// The method.

/// The can execute.

public DelegateCommand( Action < object > method, Predicate < object > canExecute)

{

this .method = method;

this .canExecute = canExecute;

}

///

/// Defines the method that determines whether the command can execute in its current state.

///

/// Data used by the command. If the command does not require data to be passed, this object can be set to null.

///

/// true if this command can be executed; otherwise, false.

///

public bool CanExecute( object parameter)

{

if (canExecute == null )

{

return true ;

}

return canExecute(parameter);

}

///

/// Defines the method to be called when the command is invoked.

///

/// Data used by the command. If the command does not require data to be passed, this object can be set to null.

public void Execute( object parameter)

{

method.Invoke(parameter);

}

///

/// Raises the event.

///

/// The instance containing the event data.

protected virtual void OnCanExecuteChanged( EventArgs e)

{

var canExecuteChanged = CanExecuteChanged;

if (canExecuteChanged != null )

canExecuteChanged(

this , e);

}

///

/// Raises the can execute changed.

///

public void RaiseCanExecuteChanged()

{

OnCanExecuteChanged(

EventArgs .Empty);

}

}

---

方法一：-----------------------------------------------------------------

　　　　　　　　　　　xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"　
　　　　　　　　　　　xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"　
　　　　　　　　　　　xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
　　　　　　　　　　　xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
　　　　　　　　　　　xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
　　　　　　　　　　　xmlns:ViewModel="clr-namespace:Silverlight40.Binding.Command"
　　　　　　　　　　　Title="Demo　Page">
　　　　
　　　　　　　　
　　　　　　　　
　　　　　　　　　　　　
　　　　　　　　
　　　　　　　　
　　　　　　　　
　　　　　　　　　　　　
　　　　　　　　　　　　
　　　　　　　　
　　　　　　　　
　　　　

Code部分：-----------------------------------------------------------------------------

using　System;
using　System.Net;
using　System.Windows;
using　System.Windows.Controls;
using　System.Windows.Documents;
using　System.Windows.Ink;
using　System.Windows.Input;
using　System.Windows.Media;
using　System.Windows.Media.Animation;
using　System.Windows.Shapes;
namespace　Silverlight40.Binding.Command
{
　　　　public　class　MyViewModel
　　　　{
　　　　　　　　//　声明一个　ICommand　类型，用于绑定到　ButtonBase　或　Hyperlink　的　Command　属性上
　　　　　　　　public　ICommand　Hello　{　get;　set;　}
　　　　　　　　public　MyViewModel()
　　　　　　　　{
　　　　　　　　　　　　//　绑定了　Hello　的命令被执行时则会调用　ExecuteHello(object　parameter)　方法
　　　　　　　　　　　　Hello　=　new　MyCommand(ExecuteHello);
　　　　　　　　}
　　　　　　　　private　void　ExecuteHello(object　parameter)
　　　　　　　　{
　　　　　　　　　　　　MessageBox.Show("Hello:　"　+　parameter.ToString());
　　　　　　　　}
　　　　}
}

或者：-------------------

private DelegateCommand clickNewButton;

        public DelegateCommand ClickNewButton
        {
            get
            {
                if (clickNewButton == null)
                {
                    clickNewButton = new DelegateCommand((parameter) =>
                    {
                        parameter.GetType().GetMethod("Show").Invoke(parameter, null);
                    });
                }
                return clickNewButton;
            }
            set { clickNewButton = value; }
        }

 

方法二：-----------------------------------------------------------------

xmlns :Interactivity="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

 

< Interactivity : Interaction.Behaviors >

< PopSearchAttributeEntityBehaviors : PopSearchAttributeEntityBehaviors >

< Interactivity : Interaction.Triggers >

< Interactivity : EventTrigger SourceName ="ButtonCancel" EventName ="Click">

< Interactivity : InvokeCommandAction CommandName ="CancelCommand" />

Interactivity : EventTrigger >

< Interactivity : EventTrigger SourceName ="ButtonOK" EventName ="Click">

< Interactivity : InvokeCommandAction CommandName ="OkClickedCommand" />

Interactivity : EventTrigger >

Interactivity : Interaction.Triggers >

PopSearchAttributeEntityBehaviors : PopSearchAttributeEntityBehaviors >

Interactivity : Interaction.Behaviors >

 

< Interactivity : Interaction.Triggers >

< Interactivity : EventTrigger SourceName ="DataGridSearchResult" EventName ="CheckBoxSelected">

< Interactivity : InvokeCommandAction Command ="{ Binding AttributesSelectedCommand }" />

Interactivity : EventTrigger >

Interactivity : Interaction.Triggers >

 

---

Behavior的Code部分：-----------------------------------------------

public class PopSearchAttributeEntityBehaviors : Behavior < ChildWindow >

{

private Collection < object > dataGridSelectRows;

public Collection < object > DataGridSelectRows

{

get { return dataGridSelectRows; }

set { dataGridSelectRows = value ; }

}

///

/// Close Menu Command

///

public ICommand CancelCommand { get ; set ; }

public ICommand OkClickedCommand { get ; set ; }

public PopSearchAttributeEntityBehaviors()

:

base ()

{

CancelCommand =

new DelegateCommand (OnCancel);

OkClickedCommand =

new DelegateCommand (OnOkClicked);

}

///

/// button Cancel

///

/// StackPanel Menu Object

public void OnCancel( object menu)

{

(

this .AssociatedObject as PopSearchAttributeEntity ).Close();

}

///

/// button ok click

///

///

public void OnOkClicked( object menu)

{

ObservableCollection < object > selectedItems = (( this .AssociatedObject as PopSearchAttributeEntity ).DataContext as PopSearchAttributeEntityViewModel ).SelectedAttributes;

((

this .AssociatedObject as PopSearchAttributeEntity ).DataContext as PopSearchAttributeEntityViewModel ).OkCallback(selectedItems);

(

this .AssociatedObject as PopSearchAttributeEntity ).Close();

}

}