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

///

<summary>

/// DelegateCommand

/// </summary>

public class DelegateCommand : ICommand

{

private Predicate<object> canExecute;

private Action<object> method;

/// <summary>

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

/// </summary>

public event EventHandler CanExecuteChanged;

/// <summary>

/// Initializes a new instance of the <see cref="DelegateCommand"/> class.

/// </summary>

/// <param name="method">The method.</param>

public DelegateCommand(Action<object> method)

:

this(method, null)

{

}

/// <summary>

/// Initializes a new instance of the <see cref="DelegateCommand"/> class.

/// </summary>

/// <param name="method">The method.</param>

/// <param name="canExecute">The can execute.</param>

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

{

this.method = method;

this.canExecute = canExecute;

}

/// <summary>

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

/// </summary>

/// <param name="parameter">Data used by the command. If the command does not require data to be passed, this object can be set to null.</param>

/// <returns>

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

/// </returns>

public bool CanExecute(object parameter)

{

if (canExecute == null)

{

return true;

}

return canExecute(parameter);

}

/// <summary>

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

/// </summary>

/// <param name="parameter">Data used by the command. If the command does not require data to be passed, this object can be set to null.</param>

public void Execute(object parameter)

{

method.Invoke(parameter);

}

/// <summary>

/// Raises the <see cref="E:CanExecuteChanged"/> event.

/// </summary>

/// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>

protected virtual void OnCanExecuteChanged(EventArgs e)

{

var canExecuteChanged = CanExecuteChanged;

if (canExecuteChanged != null)

canExecuteChanged(

this, e);

}

/// <summary>

/// Raises the can execute changed.

/// </summary>

public void RaiseCanExecuteChanged()

{

OnCanExecuteChanged(

EventArgs.Empty);

}

}

---

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

<navigation:Page　x:Class="Silverlight40.Binding.Command.Demo"　
　　　　　　　　　　　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">
　　　　<Grid　x:Name="LayoutRoot">
　　　　　　　　
　　　　　　　　<Grid.DataContext>
　　　　　　　　　　　　<ViewModel:MyViewModel　/>
　　　　　　　　</Grid.DataContext>
　　　　　　　　<!--
　　　　　　　　　　　　Command　-　指定需要关联的命令
　　　　　　　　　　　　CommandParameter　-　传递给　Command　的参数
　　　　　　　　-->
　　　　　　　　<StackPanel　HorizontalAlignment="Left"　VerticalAlignment="Top"　Orientation="Horizontal"　Height="20">
　　　　　　　　　　　　<TextBox　Name="txtName"　Text="webabcd"　/>
　　　　　　　　　　　　<Button　Content="Hello"　Command="{Binding　Hello}"　CommandParameter="{Binding　ElementName=txtName,　Path=Text　}"　/>
　　　　　　　　</StackPanel>
　　　　　　　　
　　　　</Grid>
</navigation: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; }

}

/// <summary>

/// Close Menu Command

/// </summary>

public ICommand CancelCommand { get; set; }

public ICommand OkClickedCommand { get; set; }

public PopSearchAttributeEntityBehaviors()

:

base()

{

CancelCommand =

new DelegateCommand(OnCancel);

OkClickedCommand =

new DelegateCommand(OnOkClicked);

}

/// <summary>

/// button Cancel

/// </summary>

/// <param name="state">StackPanel Menu Object</param>

public void OnCancel(object menu)

{

(

this.AssociatedObject as PopSearchAttributeEntity).Close();

}

/// <summary>

/// button ok click

/// </summary>

/// <param name="menu"></param>

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();

}

}