我的 CollectionView 中有一个标签,我需要用填充视图的 ItemsSource 列表之外的值填充它。以下代码是我要完成的示例,但似乎 CollectionView 将绑定上下文限制为仅 Items 列表。我尝试命名标签并将其设置在我的 c# 代码中,但我似乎无法访问 c# 中的标签。我想我可以在 c# 中构建整个页面,而不是使用 .xaml,但与此示例不同的是,我的实际代码使用多个模板和一个模板选择器。如果我能在不重写数小时代码的情况下解决这个问题,我会更喜欢它。
项目页面.xaml
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Class="TabTest.Views.ItemsPage"
Title="{Binding Title}"
x:Name="BrowseItemsPage">
<ContentPage.ToolbarItems>
<ToolbarItem Text="Add" Clicked="AddItem_Clicked" />
</ContentPage.ToolbarItems>
<StackLayout Padding="10">
<Label Text="{Binding TestVal}" FontSize="16" HeightRequest="20" />
<!-- ^^^^ This label displays just as expected -->
<RefreshView IsRefreshing="{Binding IsBusy, Mode=TwoWay}" Command="{Binding LoadItemsCommand}">
<CollectionView x:Name="ItemsCollectionView"
ItemsSource="{Binding Items}">
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout Padding="10">
<Label x:Name="TestV" Text="{Binding Path=BindingContext.TestVal}" />
<!-- ^^^^ I want this Label to display the TestVal string in the ViewModel -->
<Label Text="{Binding Text}"
d:Text="{Binding .}"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemTextStyle}"
FontSize="16" />
<Label Text="{Binding Description}"
d:Text="Item descripton"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="13" />
<StackLayout.GestureRecognizers>
<TapGestureRecognizer NumberOfTapsRequired="1" Tapped="OnItemSelected"></TapGestureRecognizer>
</StackLayout.GestureRecognizers>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</RefreshView>
</StackLayout>
</ContentPage>
ItemsViewModel.cs
namespace TabTest.ViewModels
{
public class ItemsViewModel : BaseViewModel
{
public ObservableCollection<Item> Items { get; set; }
public Command LoadItemsCommand { get; set; }
private string testVal;
public string TestVal // I want the value of this variable in that Label
{
get
{
return testVal;
}
set
{
testVal = value;
}
}
public ItemsViewModel()
{
Title = "Browse";
TestVal = "Value123";
Items = new ObservableCollection<Item>();
LoadItemsCommand = new Command(async () => await ExecuteLoadItemsCommand());
MessagingCenter.Subscribe<NewItemPage, Item>(this, "AddItem", async (obj, item) =>
{
var newItem = item as Item;
Items.Add(newItem);
await DataStore.AddItemAsync(newItem);
});
}
async Task ExecuteLoadItemsCommand()
{
IsBusy = true;
try
{
Items.Clear();
var items = await DataStore.GetItemsAsync(true);
foreach (var item in items)
{
Items.Add(item);
}
}
catch (Exception ex)
{
Debug.WriteLine(ex);
}
finally
{
IsBusy = false;
}
}
}
}