ItemsControl的兩種數據綁定方式

     最近在學習ItemsControl這個控件的時候，查看了MSDN上面的一個例子，而且本身作了一些修改，這裏主要使用了兩種方式來進行相應的數據綁定，一種是使用DataContext，另一種是直接將一個類綁定到前臺，其實這兩種方式原理差很少都是將數據模型的對象添加到一個ObservableCollection集合中，而後再綁定到前臺,下面分別介紹兩種綁定方式：

    第一種是將數據存儲在一個ObservableCollection集合中，而後做爲ItemsControl的DataContext對象，下面分別貼出相關的代碼：

 

<Window x:Class="TestGrid.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:TestGrid"
        Title="MainWindow" Height="350" Width="525">    
    <Grid>
        <ItemsControl Margin="10" x:Name="myItemsControl"  ItemsSource="{Binding}">          
            <ItemsControl.Template>
                <ControlTemplate TargetType="ItemsControl">
                    <Border BorderBrush="Aqua" BorderThickness="1" CornerRadius="15">
                        <ItemsPresenter/>
                    </Border>
                </ControlTemplate>
            </ItemsControl.Template>         
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <WrapPanel/>
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>         
            <ItemsControl.ItemTemplate>
                <DataTemplate DataType="{ x:Type local:DataSource}">
                    <DataTemplate.Resources>
                        <Style TargetType="TextBlock">
                            <Setter Property="FontSize" Value="18"/>
                            <Setter Property="HorizontalAlignment" Value="Center"/>
                        </Style>
                    </DataTemplate.Resources>
                    <Grid>                        
                        <Rectangle Fill="Green"/>                       
                        <Ellipse Fill="Red"/>
                        <StackPanel>
                            <TextBlock Margin="3,3,3,0" Text="{Binding Path=Priority,Mode=TwoWay}"/>
                            <TextBlock Margin="3,0,3,7" Text="{Binding Path=TaskName,Mode=TwoWay}"/>
                        </StackPanel>
                    </Grid>
                </DataTemplate>
            </ItemsControl.ItemTemplate>       
            <ItemsControl.ItemContainerStyle>
                <Style>
                    <Setter Property="Control.Width" Value="100"/>
                    <Setter Property="Control.Margin" Value="5"/>
                    <Style.Triggers>
                        <Trigger Property="Control.IsMouseOver" Value="True">
                            <Setter Property="Control.ToolTip" Value="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=Content.Description}"/>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </ItemsControl.ItemContainerStyle>
        </ItemsControl>
    </Grid>   
</Window>

    這裏須要注意的地方是 ItemsSource="{Binding}"這句必須添加，不然後臺的數據是沒法添加到前臺的，這個須要注意，這裏貼出後臺的代碼  

using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace TestGrid
{
    /// <summary>
    /// MainWindow.xaml 的交互邏輯
    /// </summary>
    public partial class MainWindow : Window
    {
        private ObservableCollection<DataSource> item = null;
        public MainWindow()
        {
            InitializeComponent();
            item = new ObservableCollection<DataSource>();
            item.Add(
                new DataSource()
                {
                    Priority = "1",
                    TaskName = "hello"
                }
                );
            item.Add(
                 new DataSource()
                {
                    Priority = "2",
                    TaskName = "whats"
                }
                );
            item.Add(
                new DataSource()
                {
                    Priority = "3",
                    TaskName = "your"
                }
               );
            item.Add(
                new DataSource()
                {
                    Priority = "4",
                    TaskName = "name"
                }
               );
            item.Add(
                new DataSource()
                {
                    Priority = "5",
                    TaskName = "can"
                }
               );
            item.Add(
                new DataSource()
                {
                    Priority = "6",
                    TaskName = "you"
                }
               );
            this.myItemsControl.DataContext = item;

        }
    }
}

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TestGrid
{
   public class DataSource :  INotifyPropertyChanged
    {
       public event PropertyChangedEventHandler PropertyChanged;
       public  DataSource()
       {
       }

       private string priority;
       public string Priority
       {
           get
           { 
               return priority; 
           }
           set 
           { 
               priority = value;
               OnPropertyChanged("Priority");
           }
       }


       private string taskname;
       public string TaskName
       {
           get
           {
               return taskname;
           }
           set
           {
               taskname = value;
               OnPropertyChanged("TaskName");
           }
       }

       protected void OnPropertyChanged(string propName)
       {
           if (PropertyChanged != null)
           {
               PropertyChanged(this, new PropertyChangedEventArgs(propName));           
           }
       
       }

       private List<DataSource> datasources;

       public List<DataSource> DataSources
       {
           get { return datasources; }
           set { datasources = value; }
       }
        
    }
}

  這裏最重要的一句就是 this.myItemsControl.DataContext = item;這個是將剛纔的集合綁定到ItemsControl控件上，這裏須要咱們的注意。

  另一種方式的數據綁定就是將一個類綁定到這個ItemsControl控件上，具體的方式以下：

  

<Window x:Class="TestGrid.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:TestGrid"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <local:MyData x:Key="myDataSource"/>
    </Window.Resources>
    <Grid>
        <ItemsControl Margin="10" x:Name="myItemsControl"  ItemsSource="{Binding Source={StaticResource myDataSource}}">          
            <ItemsControl.Template>
                <ControlTemplate TargetType="ItemsControl">
                    <Border BorderBrush="Aqua" BorderThickness="1" CornerRadius="15">
                        <ItemsPresenter/>
                    </Border>
                </ControlTemplate>
            </ItemsControl.Template>         
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <WrapPanel/>
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>         
            <ItemsControl.ItemTemplate>
                <DataTemplate DataType="{ x:Type local:DataSource}">
                    <DataTemplate.Resources>
                        <Style TargetType="TextBlock">
                            <Setter Property="FontSize" Value="18"/>
                            <Setter Property="HorizontalAlignment" Value="Center"/>
                        </Style>
                    </DataTemplate.Resources>
                    <Grid>                        
                        <Rectangle Fill="Green"/>                       
                        <Ellipse Fill="Red"/>
                        <StackPanel>
                            <TextBlock Margin="3,3,3,0" Text="{Binding Path=Priority,Mode=TwoWay}"/>
                            <TextBlock Margin="3,0,3,7" Text="{Binding Path=TaskName,Mode=TwoWay}"/>
                        </StackPanel>
                    </Grid>
                </DataTemplate>
            </ItemsControl.ItemTemplate>       
            <ItemsControl.ItemContainerStyle>
                <Style>
                    <Setter Property="Control.Width" Value="100"/>
                    <Setter Property="Control.Margin" Value="5"/>
                    <Style.Triggers>
                        <Trigger Property="Control.IsMouseOver" Value="True">
                            <Setter Property="Control.ToolTip" Value="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=Content.Description}"/>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </ItemsControl.ItemContainerStyle>
        </ItemsControl>
    </Grid>   
</Window>

   這裏咱們經過資源來引用一個類，讓後使用  ItemsSource="{Binding Source={StaticResource myDataSource}}"將這個類綁定到ItemsSource控件上面，這裏貼出相關的代碼，咱們定義了一個MyData的類，將該類做爲數據源綁定到前臺上，這個類的代碼以下

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TestGrid
{
   public class MyData:ObservableCollection<DataSource>
    {
       public MyData()
       { 
           Add (new DataSource()
                {
                    Priority = "1",
                    TaskName = "My"
                }
                );
           Add(new DataSource()
               {
                   Priority = "2",
                   TaskName = "Name"
               }
                );
           Add(new DataSource()
               {
                   Priority = "3",
                   TaskName = "Is"
               }
                );
           Add(new DataSource()
               {
                   Priority = "4",
                   TaskName = "Ye"
               }
                );
           Add(new DataSource()
               {
                   Priority = "5",
                   TaskName = "Bo"
               }
                );
       
       }
       
    }
}

  這裏面很重要的一部就是讓這個類繼承自 ObservableCollection<DataSource>，而後來添加相應的數據源，咱們在使用繼承的時候須要注意這些技巧。

  其實這兩種狀況都是將一個數據集合綁定到前臺，只不過是一些綁定的方式有所不一樣，實際的原理都是同樣的！