Question

我正在尝试从1个列表拖放到另一个列表。我试过下面的代码。它正确拖放，但不会改变文本的颜色掉落到另一个列表。（我希望下一个文本的颜色会随之改变，以便知道丢弃了哪个文本（假设为蓝色）。

我有这样的MainPage.xaml：

<UserControl x:Class="Silverlight4.DragDropListBox.MainPage"
    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:toolKit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Toolkit"
             xmlns:local="clr-namespace:Silverlight4.DragDropListBox">

    <UserControl.Resources>
        <local:StyleFunctionConverter x:Key="StyleFunctionConverter"/>
    </UserControl.Resources>

    <Grid x:Name="LayoutRoot" Background="White" HorizontalAlignment="Center" VerticalAlignment="Center">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <TextBlock Text="Drag &amp; Drop ListBox Demo" FontSize="20" FontWeight="Bold" Foreground="Red" Margin="10"  Grid.Row="0"/>
        <StackPanel Orientation="Horizontal" Margin="10" Grid.Row="1">
            <toolKit:ListBoxDragDropTarget AllowDrop="True">
                <ListBox x:Name="customerListBoxMain" Height="200" Width="200" 
                            DisplayMemberPath="Name"  Style="{Binding IsInGroup,  Converter={StaticResource StyleFunctionConverter}}">
                    <ListBox.ItemsPanel>
                        <ItemsPanelTemplate>
                            <StackPanel Orientation="Vertical"/>
                        </ItemsPanelTemplate>
                    </ListBox.ItemsPanel>
                </ListBox>
            </toolKit:ListBoxDragDropTarget>
            <TextBlock Width="20" />
            <toolKit:ListBoxDragDropTarget AllowDrop="True">
                <ListBox Height="200" Width="200" DisplayMemberPath="Name" Style="{Binding IsInGroup, Converter={StaticResource StyleFunctionConverter}}">
                    <ListBox.ItemsPanel>
                        <ItemsPanelTemplate>
                            <StackPanel Orientation="Vertical"/>
                        </ItemsPanelTemplate>
                    </ListBox.ItemsPanel>
                </ListBox>
            </toolKit:ListBoxDragDropTarget>
        </StackPanel>
    </Grid>
</UserControl>

MainPage.Xaml.cs类是：

public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();

            customerListBoxMain.ItemsSource = PersonDataProvider.GetData();
        }
    }

类PersonDataProvider.cs是：

public class PersonDataProvider
    {
        public static ObservableCollection<Person> GetData()
        {
            return new ObservableCollection<Person>
                        {
                            new Person { Name = "Akash Sharma" },
                            new Person { Name = "Vinay Sen" },
                            new Person { Name = "Lalit Narayan" },
                            new Person { Name = "Madhumita Chatterjee" },
                            new Person { Name = "Priyanka Patil" },
                            new Person { Name = "Kumar Sanu" },
                            new Person { Name = "Victor Kapoor" },
                            new Person { Name = "Shymal Sen" },
                            new Person { Name = "Alan D'Souza" },
                            new Person { Name = "Kamal Saha" },
                            new Person { Name = "Alex Chan" },
                            new Person { Name = "Rohit Sharma" },
                            new Person { Name = "Dipti Sen" },
                            new Person { Name = "Dinesh Sharma" },
                            new Person { Name = "Kamal Kapoor" },
                            new Person { Name = "Raj Kapoor" },
                            new Person { Name = "Deepa Karmakar" },
                            new Person { Name = "Sarmishtha Chakrobarty" },
                            new Person { Name = "Pranab Kumar Debnath" },
                            new Person { Name = "Hiral Grover" },
                            new Person { Name = "Munmun Patel" },
                            new Person { Name = "Santosh Kumar Sen" },
                            new Person { Name = "Sandeep Debnath" }
                        };
        }
    }

And Person.cs（Model is）

public class Person
    {
        public string Name { get; set; }
    }

和Styles.xaml（资源字典）

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Style x:Key="ListBoxTextNormalItem" TargetType="TextBlock">
        <Setter Property="Foreground">
            <Setter.Value>
                <SolidColorBrush Color='Blue' />
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

App.xaml是：

<Application xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
             x:Class="Silverlight4.DragDropListBox.App">

    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Styles.xaml"></ResourceDictionary>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>


And StyleFunctionConverter.cs is:


    public class StyleFunctionConverter : IValueConverter
        {
            public Object Convert(Object value, Type targetType, Object parameter, CultureInfo culture)
            {
                if (value == null)
                    return null;

                bool isInGroup = (bool)value;
                if (isInGroup)
                    return Application.Current.Resources["ListBoxTextNormalItem"];
                else
                    return Application.Current.Resources["ListBoxTextChangeItem"];
            }

            public Object ConvertBack(Object value, Type targetType, Object parameter, CultureInfo culture)
            {
                return null;
            }
        }

如何将已删除文字的颜色设为<SolidColorBrush Color='Blue' />？

Answer 1

我宁愿在XAML中使用DataTriggers而不是绑定你的样式。这样，您可以根据可以使用绑定访问的数据来更改样式。

这样的事情：

    <ListBox>
        <ListBox.Resources>
            <Style TargetType="ListBoxItem">
                <Setter Property="Foreground" Value="Green" />
                <Style.Triggers>
                    <DataTrigger Binding="{Binding Path=DataContext.IsInGroup}" Value="True">
                        <Setter Property="Foreground" Value="Blue"></Setter>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </ListBox.Resources>
    </ListBox>

为什么我的ListBox Drag and Drop中的文本颜色不会改变？

1 个答案: