【发布时间】：2017-01-11 07:55:12
【问题描述】：
我试图在我的 xamarin.forms 应用程序中使用手风琴。我可以毫无问题地使用它但是当我想将它与 viewmodels 一起使用时。手风琴中没有显示数据 .我的视图模型是这样的;
namespace xamarinapp
{
public class TestViewModel : ViewModelBase
{
private readonly IServiceWrapper _myServiceWrapper;
private readonly IAuthenticationService _authenticationService;
public string viemodelName { get; set; }
private bool UserLogCheck = false;
private ObservableRangeCollection<dataInfro> _Acclist;
public ObservableRangeCollection<Models.dataInfro> Acclist
{
get
{
return _Acclist;
}
set
{
_Acclist = value;
RaisePropertyChanged(() => Acclist);
}
}
public override async Task InitializeAsync(object navigationData)
{
UserLogCheck = DependencyService.Get<LoginInterface>().LoginExists();
if (!UserLogCheck)
{
NavigationService.NavigateToAsync<LoginViewModel>();
}
else
{
await getData();
}
}
public ICommand ItemSelectedCommand2 => new Command<dataInfro>(OntaptedItem);
private async void OntaptedItem(dataInfro item)
{
await NavigationService.NavigateToAsync<OgrenciNotViewModel>(item.ogrId.ToString());
}
public TestViewModel(IServiceWrapper myServiceWrapper)
{
_myServiceWrapper = myServiceWrapper;
_Acclist = new ObservableRangeCollection<dataInfro>();
}
private async Task getData()
{
ServiceWrapper serviceWrapper = new ServiceWrapper();
var loginUser = DependencyService.Get<LoginInterface>().getAccount();
var data = await _myServiceWrapper.GetDataSecure<Ogrencilik>("GetDataUrl", loginUser);
Acclist =new ObservableRangeCollection<dataInfro>(data.dataCollect);
}
}
}
而手风琴自定义控件是这样的。（来自https://kimsereyblog.blogspot.com.tr/2016/10/build-accordion-view-in-xamarinforms.html）
namespace xamarinapp
{
public class DefaultTemplate : AbsoluteLayout
{
public DefaultTemplate()
{
this.Padding = 0;
this.HeightRequest = 50;
var title = new Label { HorizontalTextAlignment = TextAlignment.Start, HorizontalOptions = LayoutOptions.StartAndExpand };
var price = new Label { HorizontalTextAlignment = TextAlignment.End, HorizontalOptions = LayoutOptions.End };
this.Children.Add(title, new Rectangle(0, 0.5, 0.5, 1), AbsoluteLayoutFlags.All);
this.Children.Add(price, new Rectangle(1, 0.5, 0.5, 1), AbsoluteLayoutFlags.All);
title.SetBinding(Label.TextProperty, "name", stringFormat: "{0:c1}");
price.SetBinding(Label.TextProperty, "balance", stringFormat: "{0:C2}");
}
}
public class AccordionView : ScrollView
{
private StackLayout _layout = new StackLayout { Spacing = 1 };
public DataTemplate Template { get; set; }
public DataTemplate SubTemplate { get; set; }
public static readonly BindableProperty ItemsSourceProperty =
BindableProperty.Create(
propertyName: "ItemsSource",
returnType: typeof(IList),
declaringType: typeof(AccordionSectionView),
defaultValue: default(IList),
propertyChanged: AccordionView.PopulateList);
public IList ItemsSource
{
get { return (IList)GetValue(ItemsSourceProperty); }
set { SetValue(ItemsSourceProperty, value); }
}
public AccordionView()
{
var itemTemplate = new DataTemplate(typeof(DefaultTemplate));
this.SubTemplate = itemTemplate;
this.Template = new DataTemplate(() => (object)(new AccordionSectionView(itemTemplate, this)));
this.Content = _layout;
}
void PopulateList()
{
_layout.Children.Clear();
foreach (object item in this.ItemsSource)
{
var template = (View)this.Template.CreateContent();
template.BindingContext = item;
_layout.Children.Add(template);
}
}
static void PopulateList(BindableObject bindable, object oldValue, object newValue)
{
if (oldValue == newValue) return;
((AccordionView)bindable).PopulateList();
}
}
public class AccordionSectionView : StackLayout
{
private bool _isExpanded = false;
private StackLayout _content = new StackLayout { HeightRequest = 0 };
private Color _headerColor = Color.FromHex("0067B7");
private ImageSource _arrowRight = ImageSource.FromFile("ic_keyboard_arrow_right_white_24dp.png");
private ImageSource _arrowDown = ImageSource.FromFile("ic_keyboard_arrow_down_white_24dp.png");
private AbsoluteLayout _header = new AbsoluteLayout();
private Image _headerIcon = new Image { VerticalOptions = LayoutOptions.Center };
private Label _headerTitle = new Label { TextColor = Color.White, VerticalTextAlignment = TextAlignment.Center, HeightRequest = 50 };
private DataTemplate _template;
public static readonly BindableProperty ItemsSourceProperty =
BindableProperty.Create(
propertyName: "ItemsSource",
returnType: typeof(IList),
declaringType: typeof(AccordionSectionView),
defaultValue: default(IList),
propertyChanged: AccordionSectionView.PopulateList);
public IList ItemsSource
{
get { return (IList)GetValue(ItemsSourceProperty); }
set { SetValue(ItemsSourceProperty, value); }
}
public static readonly BindableProperty TitleProperty =
BindableProperty.Create(
propertyName: "Title",
returnType: typeof(string),
declaringType: typeof(AccordionSectionView),
propertyChanged: AccordionSectionView.ChangeTitle);
public string Title
{
get { return (string)GetValue(TitleProperty); }
set { SetValue(TitleProperty, value); }
}
public AccordionSectionView(DataTemplate itemTemplate, ScrollView parent)
{
_template = itemTemplate;
_headerTitle.BackgroundColor = _headerColor;
_headerIcon.Source = _arrowRight;
_header.BackgroundColor = _headerColor;
_header.Children.Add(_headerIcon, new Rectangle(0, 1, .1, 1), AbsoluteLayoutFlags.All);
_header.Children.Add(_headerTitle, new Rectangle(1, 1, .9, 1), AbsoluteLayoutFlags.All);
this.Spacing = 0;
this.Children.Add(_header);
this.Children.Add(_content);
_header.GestureRecognizers.Add(
new TapGestureRecognizer
{
Command = new Command(async () =>
{
if (_isExpanded)
{
_headerIcon.Source = _arrowRight;
_content.HeightRequest = 0;
_content.IsVisible = false;
_isExpanded = false;
}
else
{
_headerIcon.Source = _arrowDown;
_content.HeightRequest = _content.Children.Count * 50;
_content.IsVisible = true;
_isExpanded = true;
// Scroll top by the current Y position of the section
if (parent.Parent is VisualElement)
{
await parent.ScrollToAsync(0, this.Y, true);
}
}
})
}
);
}
void ChangeTitle()
{
_headerTitle.Text = this.Title;
}
void PopulateList()
{
_content.Children.Clear();
foreach (object item in this.ItemsSource)
{
var template = (View)_template.CreateContent();
template.BindingContext = item;
_content.Children.Add(template);
}
}
static void ChangeTitle(BindableObject bindable, object oldValue, object newValue)
{
if (oldValue == newValue) return;
((AccordionSectionView)bindable).ChangeTitle();
}
static void PopulateList(BindableObject bindable, object oldValue, object newValue)
{
if (oldValue == newValue) return;
((AccordionSectionView)bindable).PopulateList();
}
}
}
我正在尝试像这样设置绑定
[XamlCompilation(XamlCompilationOptions.Skip)]
public partial class PageOgrenciNotModal : ContentPage
{
public PageOgrenciNotModal()
{
InitializeComponent();
}
protected override void OnBindingContextChanged()
{
base.OnBindingContextChanged();
Accorview.SetBinding(AccordionView.ItemsSourceProperty, "Acclist");
Accorview.Template.SetBinding(AccordionSectionView.TitleProperty, "Title");
Accorview.Template.SetBinding(AccordionSectionView.ItemsSourceProperty, "List");
}
}
但是什么都没有发生。（注意：获取数据没有问题，我可以使用与 listview 相同的方法没有问题）。感谢任何帮助，谢谢
【问题讨论】：
标签： c# mvvm xamarin xamarin.forms