wpf - TreeViewItem MouseDoubleClick 事件和 MvvmLight

Question

如何在下面的代码中设置CommandParameter，使其指向当前选定的项目？

<TreeView Grid.Column="0" HorizontalAlignment="Stretch" DockPanel.Dock="Left" ItemsSource="{Binding Path=ServerItems, UpdateSourceTrigger=PropertyChanged}">
<i:Interaction.Triggers>
    <i:EventTrigger EventName="MouseDoubleClick">
        <cmd:EventToCommand Command="{Binding ConnectServer}" PassEventArgsToCommand="True" CommandParameter="{Binding SelectedItem}" />
    </i:EventTrigger>
</i:Interaction.Triggers>
<TreeView.ItemTemplate>
    <HierarchicalDataTemplate ItemsSource="{Binding Databases}">
        <TextBlock Text="{Binding}" />
    </HierarchicalDataTemplate>
</TreeView.ItemTemplate>

ViewModel 代码:

public RelayCommand<ServerItem> ConnectServer {
    get;
    private set;
}

ConnectServer = new RelayCommand<ServerItem>(param => ConnectToServer(param));

public void ConnectToServer(ServerItem item) {
    MessageBox.Show(item.ToString());
}

代码执行无法到达 ConnectToServer 方法，因为抛出异常，告诉我从 System.Windows.Input.MouseButtonEventArgs 转换为类型 MadMin。 Model.ServerItem 是不可能的。

Answer 1

您需要使用 RelativeSource Binding以便从Trigger 内访问TreeView.SelectedItem 属性。尝试为您的 CommandParameter 使用此 Binding:

CommandParameter="{Binding SelectedItem, 
    RelativeSource={RelativeSource AncestorType={x:Type TreeView}}}"