c# - Xamarin Forms CollectionView 无法正确显示
问题描述
我有个问题。我创建了一个带有自定义 ViewPage 的 CollectionView 来放置具有行跨度的网格。ItemSource 是使用 ViewModel 设置的。现在,当我在 CollectionView 中滚动时,行会随机放置在屏幕上,甚至在彼此之间。
这是我的 xaml 代码:
<CollectionView ItemsSource="{Binding agentOrderList}" Margin="5,0,5,0" HeightRequest="450">
<CollectionView.ItemsLayout>
<LinearItemsLayout Orientation="Vertical" ItemSpacing="0"/>
</CollectionView.ItemsLayout>
<CollectionView.ItemTemplate>
<DataTemplate>
<local:OrderView BindingContext="{Binding }"/>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
这是视图模型:
public class VM_AgentsPage : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
private ObservableCollection<OrderBundle> _agentOrderList;
public ObservableCollection<OrderBundle> agentOrderList
{
get
{
return _agentOrderList;
}
set
{
if (_agentOrderList != value)
{
_agentOrderList = value;
OnPropertyChanged();
}
}
}
public VM_AgentsPage()
{
agentOrderList = new ObservableCollection<OrderBundle>();
LoadAgentOrders_Handler();
}
public Task LoadAgentOrders_Handler()
{
return LoadAgentOrders();
}
private async Task LoadAgentOrders()
{
IsRefreshingAgentOrders = true;
App.AgentOrderList = await App.RestService.GetAgentOrders(App.AgentId);
ObservableCollection<OrderBundle> tempAgentOrderList = new ObservableCollection<OrderBundle>();
foreach (OrderBundle orderBundle in App.AgentOrderList)
{
tempAgentOrderList.Add(orderBundle);
}
agentOrderList = tempAgentOrderList;
IsRefreshingAgentOrders = false;
}
}
最后是 OrderView.xaml.cs:
public partial class OrderView : ContentView
{
Grid grid;
public OrderView()
{
InitializeComponent();
grid = new Grid
{
ColumnDefinitions =
{
new ColumnDefinition{ Width = new GridLength(1, GridUnitType.Star)},
new ColumnDefinition{ Width = new GridLength(1, GridUnitType.Star) },
new ColumnDefinition{ Width = new GridLength(1, GridUnitType.Star) },
new ColumnDefinition{ Width = new GridLength(1, GridUnitType.Star) },
new ColumnDefinition{ Width = new GridLength(1, GridUnitType.Star) }
}
};
grid.RowSpacing = 0;
this.Content = grid;
this.BindingContextChanged += View1_BindingContextChanged;
}
private void View1_BindingContextChanged(object sender, EventArgs e)
{
var obj = this.BindingContext as OrderBundles;
if (obj != null)
{
List<Trade> list = obj.Trades;
for(int i = 0; i < list.Count; i++)
{
grid.RowDefinitions.Add(new RowDefinition { Height = new GridLength(20) });
Trade trade = list[i];
grid.Children.Add(new Label
{
Text = trade.Date
}, 0, i);
grid.Children.Add(new Label
{
Text = trade.Action
}, 1, i);
grid.Children.Add(new Label
{
Text = trade.Coin
}, 2, i);
grid.Children.Add(new Label
{
Text = trade.Price.ToString()
}, 3, i);
}
Label label = new Label
{
Text = list[0].ProfitUSDT,
TextColor = Color.Green ,
VerticalTextAlignment = TextAlignment.Center
};
grid.Children.Add(label, 4, 0);
Grid.SetRowSpan(label, list.Count);
}
}
}
这是什么原因造成的?
解决方案
推荐阅读
- asp.net - Angular 10 在编辑组件的下拉列表中设置选定的选项值
- c# - 使用 Oauth2 从 Xero API 获取基于联系人姓名的联系人详细信息
- django - Django (DRF) 序列化程序和 MariDB 版本控制表
- vba - 强制人们启用 Word 宏
- typescript - Svelte 允许无效的打字稿
- python - 单个位置索引器超出范围
- java - JavaFX 11 可编辑组合框抛出 IndexOutOfBoundsException
- sql - 如果控件为空(IS NULL),则访问多条件查询以包括空白/空记录
- c - STM32G0 bootloader内存扩展问题
- html - 在 div 的标题内显示实体定义