组合框自定义下拉菜单（弹出式）模板和更(Combobox with custom dropdown(

我有挂接在我的自定义下拉或弹出模板中的一些事件在我的组合框的一个问题。

顺便说一下这个自定义模板看起来像一个在IE 10。这里的图片我得到了部分查找（下面的一个是我的）。但我有删除历史列表中的项目的问题。下面是我PART_Popup模板

<Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
    <Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MinWidth="{Binding ActualWidth, ElementName=Placement}">
        <Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
            <!--<ScrollViewer>-->
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="*" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>

                <StackPanel>
                    <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>

                    <Border Padding="5">
                        <StackPanel>
                            <Grid>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="Auto" />
                                    <ColumnDefinition Width="*" />
                                </Grid.ColumnDefinitions>
                                <TextBlock Text="History" Foreground="{StaticResource SeparatorLine}" />
                                <Border Height="2" Grid.Column="1" Margin="5,0,0,0" BorderBrush="{StaticResource SeparatorLine}" BorderThickness="0.5" />
                            </Grid>
                            <ListBox x:Name="listHistory"  BorderThickness="0" Margin="0" Padding="0" HorizontalContentAlignment="Stretch">
                                <ListBox.ItemTemplate>
                                    <DataTemplate>
                                        <Grid>
                                            <TextBlock Text="{Binding }" />
                                            <Button Grid.Column="1" HorizontalAlignment="Right" x:Name="btnDeleteHistoryItem" Content="r" FontFamily="Marlett" Style="{DynamicResource ButtonStyle}" Visibility="Hidden" Opacity="0.75" />
                                        </Grid>

                                        <DataTemplate.Triggers>
                                            <Trigger Property="IsMouseOver" Value="True">
                                                <Setter Property="Visibility" TargetName="btnDeleteHistoryItem" Value="Visible" />
                                            </Trigger>
                                        </DataTemplate.Triggers>
                                    </DataTemplate>
                                </ListBox.ItemTemplate>
                            </ListBox>
                    </StackPanel>
                    </Border>
                </StackPanel>

                <Border Grid.Row="1" BorderBrush="{StaticResource SeparatorLine}" BorderThickness="0,1,0,0" Padding="5" Height="30">
                    <Border.Background>
                        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                            <GradientStop Color="#33000000" Offset="0"/>
                            <GradientStop Offset="1"/>
                            <GradientStop Offset="0.375"/>
                        </LinearGradientBrush>
                    </Border.Background>

                    <StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
                        <Button x:Name="btnClearHistory" Content=" Clear History " Style="{DynamicResource ButtonStyle}" />
                    </StackPanel>
                </Border>
            </Grid>
            <!--</ScrollViewer>-->
        </Border>
    </Themes:SystemDropShadowChrome>
</Popup>

好吧，在列表框中（listHistory）我有一个按钮那里叫btnDeleteHistoryItem，我不能把它捞起来。它在我的代码在这里返回一个空的错误

protected override void OnSourceInitialized(EventArgs e)
{
    ListBox lb = (ListBox)cbSearch.Template.FindName("listHistory", cbSearch);
    lb.ItemsSource = this.SearchHistory;
    lb.SelectionChanged += cbResults_SelectionChanged;

    Button btnDeleteHistoryItem = (Button)lb.Template.FindName("btnDeleteHistoryItem", lb);
    // if (btnDeleteHistoryItem != null)
    {
        btnDeleteHistoryItem.Click += DeleteHistoryItem_Click;
    }

    // or --------------

    Button btnDeleteHistoryItem = (Button)cbSearch.Template.FindName("btnDeleteHistoryItem", cbSearch);
    // if (btnDeleteHistoryItem != null)
    {
        btnDeleteHistoryItem.Click += DeleteHistoryItem_Click;
    }
}

编码是这里一点经典，所以在事件挂钩没有实施MVVM。因此，问题是这样的按钮btnDeleteHistoryItem =（按钮）lb.Template.FindName（ “btnDeleteHistoryItem”，磅）; 或按钮btnDeleteHistoryItem =（按钮）cbSearch.Template.FindName（ “btnDeleteHistoryItem”，cbSearch）; 行如不能找到btnDeleteHistoryItem。

我怎样才能解决这个问题？

- 更新 -

lb.Loaded += (a, b) =>
{
    Button btnDeleteHistoryItem = (Button)lb.Template.FindName("btnDeleteHistoryItem", lb);
    //if (btnDeleteHistoryItem != null)
    {
        btnDeleteHistoryItem.Click += DeleteHistoryItem_Click;
    }
};

不工作，要么

使用命令可能会在这里最简单的解决方案。您可以挂钩一个命令到你的删除按钮和作为参数传递当前项目。这里有一个简单的示例来说明。

public partial class MainWindow : Window {
    public MainWindow() {
        InitializeComponent();
        SomeCommand = new MySampleCommand();

        cbo.Items.Add("Hello");
        cbo.Items.Add("Item 1");
        cbo.Items.Add("Another Item");
        cbo.Items.Add("Something else");
        cbo.Items.Add("Yet another item");
    }

    public MySampleCommand SomeCommand { get; set; }
}

public class MySampleCommand : ICommand {
    public bool CanExecute(object parameter) {
        return true;
    }

    public event EventHandler CanExecuteChanged;

    public void Execute(object parameter) {
        MessageBox.Show(string.Format("You are trying to remove {0}", parameter.ToString()));
    }
}

你的组合框结合看起来是这样的：

<Window x:Class="SOComboWithEmbeddedButton2.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Name="Window"
    Title="MainWindow" Height="350" Width="525">
<Window.Resources>
    <DataTemplate x:Key="ListBoxItemTemplate">
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="{Binding}" />
            <Button Command="{Binding SomeCommand, ElementName=Window}" CommandParameter="{Binding}" Content="Remove" />
        </StackPanel>
    </DataTemplate>
</Window.Resources>
<StackPanel>
    <ComboBox ItemTemplate="{StaticResource ListBoxItemTemplate}" x:Name="cbo" />
</StackPanel>

只要调整在DataTemplate中命令结合指向具有您的命令对象的实例，合适的对象。希望帮助！