WPF ListBox - Beginning

ListBox可以讓使用者能夠從清單選取某個項目, 它是一個項目的控制項, 可以包含物件(object)的集合.

ListBox繼承自ItemControl, 它可以透過Items(型別為object collection)和 ItemsSource(有實踐IEnumerable的物件)這兩個屬性 , 來將任何物件放入ListBox中, 如果放入的項目不是UIElement(例如:數值或string), 則會呼叫物件的ToString()函式, 然後將資料放入TextBlock中.

將物件放入ListBox有兩種方法:

• 利用Items屬性加入項目(Add)

下面的程式碼說明利用Items將任一物件放到ListBox中:

XAML檔如下:

<Window
x:Class="ListBoxTemplate.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
Title="ListBox" Height="300" Width="300">
<Grid>
<ListBox Margin="10" Name="listBox1">

    <ListBoxItem Foreground="Aqua">Text</ListBoxItem>

    <ListBoxItem>
        <sys:DateTime>8/20/2009</sys:DateTime>
    </ListBoxItem>

    <ListBoxItem>
        <Button Content="Button"
                Background="LavenderBlush"
                Foreground="Green"
                Width="60"
                Height="30"/>
    </ListBoxItem>

    <ListBoxItem>
        <StackPanel>
            <Rectangle Width="50"
                       Height="50"
                       Fill="Chartreuse"
                       Stroke="LightSlateGray"
                       StrokeThickness="3"/>
            <TextBlock Text="Multiple objects in Panel"
                       FontSize="16"
                       Foreground="Red"/>
        </StackPanel>
    </ListBoxItem>
</ListBox>
</Grid>
</Window>

C#檔如下:

Grid grid = new Grid();
ListBox listBox1 = new ListBox();  
listBox1.Margin = new Thickness(10);

grid.Children.Add(listBox1);

// Add a string object to a ListBox.
listBox1.Items.Add("Text");

// Add a DateTime object to a ListBox
DateTime dateTime = new DateTime(2009, 8, 20);
listBox1.Items.Add(dateTime);

// Add a button object to a ListBox
Button button1 = new Button();
button1.Content = "Button";
button1.Background = Brushes.LavenderBlush;
button1.Foreground = Brushes.Green;
button1.Width = 60;
button1.Height = 30;
listBox1.Items.Add(button1);

// Add a stackpanel that contains multpile objects to the ListBox.
StackPanel panel = new StackPanel();

Rectangle rect = new Rectangle();
rect.Width = 50;
rect.Height = 50;
rect.Fill = Brushes.Chartreuse;
rect.Stroke = Brushes.LightSlateGray;
rect.StrokeThickness = 3;

TextBlock txtBlock = new TextBlock();
txtBlock.Text = "Multiple objects in Panel";
txtBlock.FontSize = 16;
txtBlock.Foreground = Brushes.Red;

panel.Children.Add(rect);
panel.Children.Add(txtBlock);
listBox1.Items.Add(panel);

this.AddChild(grid);

[圖 1] 利用Items加物件

• 將ItemsSource 繫結到一個物件的集合
  

你可以讓ItemsSource等於一個物件的集合, 或是將ItemsSource繫結(Binding)至集合物件,
注意: 當設定ItemsSource 屬性設定時, 會將 Items 集合設為唯讀和固定大小, 因此不能再對Items作新增或移除. 若將ItemsSource 屬性設為 null, 則會移除集合, 並將用法還原為 Items.

下面的範例說明, 如何利用ItemSource去Binding一個物件:
首先, 我們先建立一個WeekData 的物件,如下:

 public class WeekData : ObservableCollection<string>
{
public WeekData()
{
    Add("Sun");
    Add("Mon");
    Add("Tue");
    Add("Wed");
    Add("Thu");
    Add("Fri");
    Add("Sat");
}
}

將ItemsSource 繫結至 WeekData:

Grid grid = new Grid();
ListBox listBox = new ListBox();
WeekData weekData = new WeekData();
Binding binding = new Binding();

binding.Source = weekData;
listBox.SetBinding(ListBox.ItemsSourceProperty, binding);
grid.Children.Add(listBox);
this.AddChild(grid);

如果您想要從 XAML中 繫結的CLR物件, 可以將物件定義為資源, 並指定x:Key,如下所示:

<Window.Resources>
<c:WeekData x:Key="weekData"/>
</Window.Resources>

<ListBox ItemsSource="{Binding Source={StaticResource weekData}}"/>

[圖 2] 利用ItemSource加入物件

參考文件:
MSDN-Controls 內容模型概觀
MSDN- ListBox Class