Question

我有listview有两个动态操作label和button的视图，我试图访问按钮点击按钮点击进入详细信息页面。

下面的

是我的自定义ViewCell

protected override async void OnAppearing()
{
    listClass.ItemsSource = list;
    listClass.ItemTemplate = new DataTemplate(typeof(ItemTemplateViewCell )); 
}

public class ItemTemplateViewCell : ViewCell
{

    Label NameLbl = new Label();
    StackLayout sLayout = new StackLayout ();
    Button btnViewcell = new Button {Text = "Show class details"};
    public ItemTemplateViewCell()
    {
        NameLbl.SetBinding(Label.TextProperty, "Name");
        sLayout.Children.Add(NameLbl);
        btnViewcell.Clicked += (s, e) =>
        {
            // Navigation.PushAsync(new Home()); //I can not using this line 
            // does not exist in the current context, why cant i navigate to 
            // another page from inside datatemplate in List view
        };
        sLayout.Children.Add(btnViewcell);
        this.View = sLayout;
    }
}

Answer 1

您可以通过构造函数将导航传递给ViewCell：

    public class ItemTemplateViewCell : ViewCell
    {
        // Navigation Mermber
        INavigation MyNavigation;
        Label NameLbl = new Label();
        StackLayout sLayout = new StackLayout ();
        Button btnViewcell = new Button {Text = "Show class details"};
        public ItemTemplateViewCell(INavigation navigation)
        {
            MyNavigation = navigation;
            NameLbl.SetBinding(Label.TextProperty, "Name");
            sLayout.Children.Add(NameLbl);
            btnViewcell.Clicked += ButtonShowDetails_Clicked;
            sLayout.Children.Add(btnViewcell);
            this.View = sLayout;
        }

        private void ButtonShowDetails_Clicked(object sender, EventArgs e)
        {                                                  
             MyNavigation.PushAsync(new Home());
        }
    }

然后通过委托函数

传递导航

    protected override async void OnAppearing()
    {
       listClass.ItemsSource = list;
       listClass.ItemTemplate = new DataTemplate(Function) ; 
    }

    public object Function()
    {
        return new ItemTemplateViewCell (Navigation);
    }

然后您可以在ViewCell中访问Navigation对象

Answer 2

您只需使用CommandParameterProperty绑定：

示例：

ListViewClass.ItemTemplate = new DataTemplate(() =>
{
  var GoHomeButton = new Button { Text = "Go Home", HorizontalOptions = LayoutOptions.StartAndExpand };
  GoHomeButton.SetBinding(Button.CommandParameterProperty, new Binding("Name"));
  GoHomeButton.Clicked += Gohome;
//return new view cell 
 }
    private void Gohome(object sender, EventArgs e)
    {      
            Navigation.PushAsync(new Home());
    }

有关详细信息，请查看以下链接：

http://www.c-sharpcorner.com/blogs/handling-child-control-event-in-listview-using-xamarinforms1

Answer 3

我认为出错的是您在课程初始化中立即执行操作。你应该把它分开，如下所示。另一个问题是您在方法之外进行变量初始化。这可能没问题，但我更喜欢以下代码：

public class ItemTemplateViewCell : ViewCell
{

    Label nameLbl;
    StackLayout sLayout;
    Button btnViewcell;
    public ItemTemplateViewCell()
    {
        nameLbl = new Label()
        sLayout = new StackLayout ()
        btnViewcell = new Button {Text = "Show class details"};

        NameLbl.SetBinding(Label.TextProperty, "Name");
        sLayout.Children.Add(NameLbl);
        btnViewcell.Clicked += OnButtonClicked;
        sLayout.Children.Add(btnViewcell);
        this.View = sLayout;
    }

    void OnButtonClicked(object sender, EventArgs e)
    {
        Navigation.PushAsync(new Home()); 
    }
}

我认为这应该适合你的情况，但我不能确定。我不认为你发布的是你的代码一对一，因为我没有在你的代码中看到s和e的任何初始化，并且在评论中提到代码中的注释会导致问题，如果你真的把它作为问题。此外，您不共享Home类的代码。那方面可能有些错误。

Answer 4

Navigation在ViewCell内无法使用，这意味着您无法直接从ViewCell访问它。但这应该有效：

App.Current.MainPage.Navigation.PushAsync(new Home());

整个代码：

protected override async void OnAppearing()
{
    listClass.ItemsSource = list;
    listClass.ItemTemplate = new DataTemplate(typeof(ItemTemplateViewCell )); 
}

public class ItemTemplateViewCell : ViewCell
{

    Label NameLbl = new Label();
    StackLayout sLayout = new StackLayout ();
    Button btnViewcell = new Button {Text = "Show class details"};
    public ItemTemplateViewCell()
    {
        NameLbl.SetBinding(Label.TextProperty, "Name");
        sLayout.Children.Add(NameLbl);
        btnViewcell.Clicked += (s, e) =>
        {
            App.Current.MainPage.Navigation.PushAsync(new Home());
        };
        sLayout.Children.Add(btnViewcell);
        this.View = sLayout;
    }
}

如何在Xamarin.Forms中访问listview datatemplate内的按钮？

4 个答案: