如何选择项目 MVVM listview - Xamarin 表单

Posted 2023-04-13

【中文标题】如何选择项目 MVVM listview - Xamarin 表单

【英文标题】：How selected item MVVM listview - Xamarin form

【发布时间】：2020-08-04 00:13:34

【问题描述】：

如何在 listview Mvvm 中选择项目我的代码不起作用

我的代码项目来源：

protected async override void OnAppearing()
    
        base.OnAppearing();
        var allPersons = await firebaseHelper.GetAllCamps();
        lstCampus.ItemsSource = allPersons;
    

我的代码选择项：

void OnItemTapped(object sender, System.EventArgs e)
    
        if (lstCampus.SelectedItem != null)
            DisplayAlert("OnItemTapped", lstCampus.SelectedItem.ToString(), "OK");
    

我的模型：

public class Campus

    public string NameCamp  get; set; 

我的视图模型：

public async Task<List<Campus>> GetAllCamps()
    

        return (await firebase
          .Child("Camps")
          .OnceAsync<Campus>()).Select(item => new Campus
          
              NameCamp = item.Object.NameCamp
          ).ToList();
    

谢谢你

【参考方案1】：

您可以尝试使用行为。这将帮助您：

https://www.c-sharpcorner.com/article/xamarin-forms-eventtocommand-behavior-in-mvvm-viewmodel/

https://docs.microsoft.com/en-US/xamarin/xamarin-forms/app-fundamentals/behaviors/reusable/event-to-command-behavior

之后，只需将这样的内容添加到您的列表中：

                <ListView.Behaviors>
                    <b:EventToCommandBehavior EventName="ItemTapped" Command="Binding TappedCamp" InputConverter="StaticResource ItemTappedConverter"/>
                </ListView.Behaviors>

【参考方案2】：

使用List.ItemTapped 或ListView.ItemSelected 事件，当一个项目被选中时它们都会被引发。

ItemTapped

listview.ItemTapped += Listview_ItemTapped;
private void Listview_ItemTapped(object sender, ItemTappedEventArgs e)
    
        DisplayAlert("OnItemTapped", (e.Item as Campus).NameCamp , "OK");
    

项目选择

listview.ItemSelected += Listview_ItemSelected;

private void Listview_ItemSelected(object sender, SelectedItemChangedEventArgs e)
    
        DisplayAlert("OnItemTapped", (e.SelectedItem as Campus).NameCamp, "OK");