如何知道点击了contextAction menuItem的listView viewCell?

How to know the listView viewCell whose contextAction menuItem is clicked?

我在 xaml 中创建了一个 listView(使用 xamarin 在线跨平台开发指南),如下所示:

<ListView x:Name="AccountsList" ItemSelected="AccountSelected">
    <ListView.ItemTemplate>
      <DataTemplate>
        <ViewCell>
        <ViewCell.ContextActions>
            <MenuItem Clicked="OnEdit"     
               Text="Edit" />
            <MenuItem Clicked="OnDelete"     
               Text="Delete" IsDestructive="True" />
         </ViewCell.ContextActions> 
          <ViewCell.View>
              <StackLayout Orientation="Vertical"
                           HorizontalOptions="StartAndExpand">

                <Label Text="{Binding DeviceName}"
                       HorizontalOptions="CenterAndExpand"/>
              </StackLayout>
          </ViewCell.View>
        </ViewCell>
      </DataTemplate>
    </ListView.ItemTemplate>
  </ListView>

我像这样以编程方式分配 ItemSource:AccountsList.ItemsSource = App.Database.GetAccounts ();

这是我的 'onDelete' 方法:

public void OnDelete (object sender, EventArgs e) { 
    var mi = ((MenuItem)sender); 
    DisplayAlert("Delete Context Action", mi.Command + " delete context action", "OK"); 
}

我想知道具体是哪个viewCell的menuItem被点击了,即从上面的'onDelete'方法中引用对象的'DeviceName'。我知道我可以用这样的 listView 的 'ItemSelected' 方法来做到这一点:

void AccountSelected(object sender, SelectedItemChangedEventArgs e)
{
    var _account = (Account)e.SelectedItem;
    // And access the account here.
}

但是 'Clicked' 方法不允许 'void OnDelete (object sender, SelectedItemChangedEventArgs e)' 签名(而且我怀疑它是否会起作用)。

我怎样才能做到这一点?

您可以像下面的例子一样绑定行的记录id,

<MenuItem Clicked="OnDelete" Text="Delete" IsDestructive="True" CommandParameter="{Binding RecordIdentifier}"/>

并且在您的 OnDelete 事件处理程序上,您可以从 CommandParameter 中获取我们之前绑定的记录 ID,类似于下面的示例,

public void OnDelete (object sender, EventArgs e) 
 { 
      var mi = ((MenuItem)sender); 
      DisplayAlert("Delete Context Action", mi.CommandParameter + " delete context action", "OK"); 
 }