WPF TextWrap與ListBox和ContentControl之間的區別

Question

我有一個列表框，其數據模板包含一個網格。網格里面我有一個TextBlock，但我不能讓TextWrapping物業工作正常：我寫了一個樣本來說明問題：

XAML：

<Window x:Class="MyTest.Test" 
    xmlns:my="clr-namespace:MyTest" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Title="Test" > 
<Window.Resources> 
    <DataTemplate DataType="{x:Type my:Task}"> 
     <Border BorderThickness="2" BorderBrush="Red"> 
      <Grid ShowGridLines="True"> 
       <Grid.ColumnDefinitions> 
        <ColumnDefinition Width="*"/> 
        <ColumnDefinition Width="*" /> 
       </Grid.ColumnDefinitions> 
       <TextBlock MaxWidth="50" Margin="3" Grid.Column="0" TextWrapping="Wrap" Text="{Binding Path=Description}"></TextBlock> 
       <TextBlock Margin="3" Grid.Column="1" TextWrapping="Wrap" Text="{Binding Path=LongDescription}"></TextBlock> 
      </Grid> 
     </Border> 
    </DataTemplate> 
</Window.Resources> 
<StackPanel> 

    <TextBlock FontWeight="Bold" TextWrapping="Wrap">ContentControl: the textwrapping works as expected (select a row in the first listbox)</TextBlock> 
    <ContentControl MinHeight="10" Content="{Binding ElementName=lsTask, Path=SelectedItem}" /> 

    <TextBlock FontWeight="Bold" TextWrapping="Wrap">ListBox: I can't get the textwrapping work properly</TextBlock> 
    <ListBox MinHeight="10" Name="lsTask" ItemsSource="{Binding Path=TaskList}" ></ListBox> 

    <TextBlock FontWeight="Bold" TextWrapping="Wrap">ListBox 2 : I tried with HorizontalContentAlignment="Stretch": similar but doesn't wrap</TextBlock> 
    <ListBox MinHeight="10" Name="lsTask2" ItemsSource="{Binding Path=TaskList}" HorizontalContentAlignment="Stretch" ></ListBox> 



    <TextBlock FontWeight="Bold" TextWrapping="Wrap">ListBox 3: I can wrap only setting Width in the datatemplate</TextBlock> 
    <ListBox MinHeight="10" Name="lsTask3" ItemsSource="{Binding Path=TaskList}" HorizontalContentAlignment="Stretch" > 
     <ListBox.ItemTemplate> 
      <DataTemplate> 
       <Border BorderThickness="2" BorderBrush="Green"> 
        <Grid ShowGridLines="True"> 
         <Grid.ColumnDefinitions> 
          <ColumnDefinition Width="*"/> 
          <ColumnDefinition Width="*" /> 
         </Grid.ColumnDefinitions> 

         <TextBlock Margin="3" Grid.Column="0" TextWrapping="Wrap" Text="{Binding Path=Description}"></TextBlock> 
         <TextBlock Width="200" Margin="3" Grid.Column="1" TextWrapping="Wrap" Text="{Binding Path=LongDescription}"></TextBlock> 
        </Grid> 
       </Border> 
      </DataTemplate> 
     </ListBox.ItemTemplate> 


    </ListBox> 
</StackPanel> 

這是我 代碼隱藏：

namespace MyTest 
{ 

public class Task 
{ 
    public string Description { get; set; } 
    public string LongDescription { get; set; } 

} 

public class MyContext 
{ 
    public List<Task> TaskList { get; set; } 

    public MyContext() 
    { 
     TaskList = new List<Task>(); 
     TaskList.Add(new Task() { Description = "description1", LongDescription = "long long long long long long long long description1" }); 
     TaskList.Add(new Task() { Description = "description2", LongDescription = "long long long long long long long long description2" }); 
     TaskList.Add(new Task() { Description = "description3", LongDescription = "long long long long long long long long description3" }); 
    } 

} 


public partial class Test : Window 
{ 

    public Test() 
    { 
     DataContext = new MyContext(); 
     InitializeComponent(); 

    } 
} 
} 

在ContentControl和前兩個ListBox中我使用相同的數據模板;在ContentControl中，WordWrapping按預期工作（無論何時調整窗口大小），而在ListBox中則不會。有什麼不同？

我發現使TextWrapping在ListBox中工作的唯一方法是修復TextBlock的Width（或MaxWidth），但它不是所需的行爲。

謝謝， 的Alessandro

Answer 1

列表框包含的ScrollViewer，所以當內容要爲比滾動條會自動出現列表框寬。解決方法是禁用水平滾動條。

<ListBox ... ScrollViewer.HorizontalScrollBarVisibility="Disabled"/>