Mahapps WPF - 组合框绑定的奇怪行为

Question

当我将图标添加到 ComboBox.ItemTemplate 时，我遇到了一种奇怪的行为。 最初加载项目后，所有项目都显示了相应的图标，但是当我选择一个项目时，图标会显示在 Combo Part 中，但会在 Expander Part 中消失。

You can see the problem here (imgur)

我在 WPF/C# 方面没有经验，我绑定项目或 ComboBox.ItemTemplate 的方式有问题吗？

非常感谢您的帮助。-

XAML 代码

    <ComboBox x:Name="comboBox" HorizontalAlignment="Left" Height="32" Margin="60,47,0,0" VerticalAlignment="Top" Width="282" ItemsSource="{Binding OtherTasks}" >
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <DockPanel Margin="0" Height="30">
                    <ContentControl Content="{Binding Path=Icono}" Margin="0,4,0,0" Background="Yellow" Width="16" Height="16" Visibility="Visible"/>
                    <AccessText HorizontalAlignment="Stretch" Margin="3,4,0,0" Text="{Binding Path=Text}" TextAlignment="Left" Width="Auto" />
                </DockPanel>
            </DataTemplate>
        </ComboBox.ItemTemplate>
    </ComboBox>

CS 代码

namespace test___icon {
    public partial class MainWindow : MetroWindow {

        public class CLASS_OTHERTASKS {
            public string Text { get; set; }
            public object Icono { get; set; }
        }

        public List<CLASS_OTHERTASKS> OtherTasks { get; set; }

        public MainWindow() {
            OtherTasks = new List<CLASS_OTHERTASKS>();
            OtherTasks.Add(new CLASS_OTHERTASKS() { Text = "Test Air", Icono = new PackIconEntypo() { Kind = PackIconEntypoKind.Air } });
            OtherTasks.Add(new CLASS_OTHERTASKS() { Text = "Test Account", Icono = new PackIconMaterial() { Kind = PackIconMaterialKind.Account } });
            OtherTasks.Add(new CLASS_OTHERTASKS() { Text = "Test AxisThree", Icono = new PackIconModern() { Kind = PackIconModernKind.AxisThree } });

            InitializeComponent();
            this.DataContext = this;
        }
    }
}

Answer 1

控件只能在可视化树中出现一次，因此从数据绑定属性返回控件并不是一个好主意。您最好在 XAML 标记中定义可视控件。像这样的：

<ComboBox x:Name="comboBox" ItemsSource="{Binding OtherTasks}" >
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <DockPanel Margin="0" Height="30">
                <ContentControl x:Shared="False" Content="{Binding}" Margin="0,4,0,0" Background="Yellow" Width="16" Height="16" Visibility="Visible">
                    <ContentControl.Style>
                        <Style TargetType="ContentControl">
                            <Style.Triggers>
                                <DataTrigger Binding="{Binding Text}" Value="Test Air">
                                    <Setter Property="ContentTemplate">
                                        <Setter.Value>
                                            <DataTemplate>
                                                <iconPacks:PackIconEntypo Kind="Air" />
                                            </DataTemplate>
                                        </Setter.Value>
                                    </Setter>
                                </DataTrigger>
                                <DataTrigger Binding="{Binding Text}" Value="Test Account">
                                    <Setter Property="ContentTemplate">
                                        <Setter.Value>
                                            <DataTemplate>
                                                <iconPacks:PackIconMaterial Kind="Account" />
                                            </DataTemplate>
                                        </Setter.Value>
                                    </Setter>
                                </DataTrigger>
                                <DataTrigger Binding="{Binding Text}" Value="Test AxisThree">
                                    <Setter Property="ContentTemplate">
                                        <Setter.Value>
                                            <DataTemplate>
                                                <iconPacks:PackIconModern Kind="AxisThree" />
                                            </DataTemplate>
                                        </Setter.Value>
                                    </Setter>
                                </DataTrigger>
                            </Style.Triggers>
                        </Style>
                    </ContentControl.Style>
                </ContentControl>
                <AccessText HorizontalAlignment="Stretch" Margin="3,4,0,0" Text="{Binding Path=Text}" TextAlignment="Left" Width="Auto" />
            </DockPanel>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>