获取longlistselector中选中项的索引 [英] Get the index of the selected item in longlistselector

问题描述

我有一个很长的列表选择器

I have a long list selector

<phone:LongListSelector x:Name="BTDevices"  SelectionChanged="BTDevices_SelectionChanged_1">
 <phone:LongListSelector.ItemTemplate>
  <DataTemplate>
   <StackPanel>
    <TextBlock Text="{Binding Path=Name}" FontSize="30" />
   </StackPanel>
  </DataTemplate>
 </phone:LongListSelector.ItemTemplate>
</phone:LongListSelector>

函数定义为:

private void BTDevices_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
//here i want to get the index of the selected item
}

我尝试了以下行

int a = App.ViewModel.Items.IndexOf(sender as ItemViewModel);

但它总是返回-1.

推荐答案

当 SelectionChanged 事件发生时，事件处理程序的 sender 参数表示触发此事件的对象事件.它属于 Object 类型，但您可以将其转换为匹配您的特定控件类型.

When the SelectionChanged event occurs, the senderparameter of the event handler represents the object that triggered this event. It is of type Object, but you can cast it to match your specific control type.

在这种情况下，LongListSelector :

var myItem = ((LongListSelector) sender).SelectedItem as Model;

(模型代表您的控件处理的数据类型).

(Model represents the type of data your control handles).

之后，在 ItemsSource 中查找该项目并检索其值:

Afterwards, look for that item in the ItemsSource and retrieve its value :

var myIndex = ((LongListSelector) sender).ItemsSource.IndexOf(myItem);

您已经命名了您的控件，因此您可以使用其名称 BTDevices 而不是 (sender as LongListSelector)，但我编写的代码行旨在显示sender 对象是什么.

You have named your control, so instead of (sender as LongListSelector), you could use its name, BTDevices, but the code lines I wrote was intended to show you what's what with the sender object.

或者(这是一种更优雅的方式)，如 bland 所示，您可以使用 EventArgs 进行选择:e.AddedItems[0]

Alternatively (and this is a more elegant way), shown by bland, you could use the EventArgs for selection : e.AddedItems[0]

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