Question

我正在尝试将我的视图绑定到没有DataObjectProvider的视图模型。

以下代码运行时没有错误，但我的ListBox 为空。

据我所知，我没错：

将View的DataContext设置为ViewModel本身（DataContext = new CustomersViewModel();）
在ViewModel（public static ObservableCollection<Customer> GetAll()）
将ListBox绑定到客户对象（ItemsSource="{Binding GetAll}"）

我在这里缺少什么样的语法？

CustomersView.xaml：

<UserControl x:Class="TestDynamicForm123.View.CustomersView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <UserControl.Resources>
        <Style x:Key="allCustomersListBox" TargetType="ListBox">
            <Setter Property="BorderThickness" Value="0"/>
        </Style>
        <DataTemplate x:Key="allCustomersDataTemplate">
            <StackPanel Orientation="Horizontal">
                <TextBlock Text="{Binding FirstName}"/>
                <TextBlock Text=" "/>
                <TextBlock Text="{Binding LastName}"/>
            </StackPanel>
        </DataTemplate>
    </UserControl.Resources>

    <StackPanel Style="{StaticResource viewWrappingStackPanel}">
        <ListBox ItemsSource="{Binding GetAll}"
                 ItemTemplate="{StaticResource allCustomersDataTemplate}"
                 Style="{StaticResource allCustomersListBox}">
        </ListBox>
    </StackPanel>
</UserControl>

CustomersView.xaml.cs：

using System.Windows.Controls;
using TestDynamicForm123.ViewModel;

namespace TestDynamicForm123.View
{
    public partial class CustomersView : UserControl
    {
        public CustomersView()
        {
            InitializeComponent();

            DataContext = new CustomersViewModel();
        }
    }
}

CustomersViewModel.cs：

using System.Collections.ObjectModel;

namespace TestDynamicForm123.ViewModel
{
    public class CustomersViewModel
    {
        public static ObservableCollection<Customer> GetAll()
        {
            return Customer.GetAll();
        }
    }
}

Customer.cs：（型号）

using System.Collections.ObjectModel;

namespace TestDynamicForm123.ViewModel
{
    public class Customer
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Age { get; set; }

        public static ObservableCollection<Customer> GetAll()
        {
            ObservableCollection<Customer> customers = new ObservableCollection<Customer>();
            customers.Add(new Customer() { FirstName = "Jay", LastName = "Anders", Age = 34 });
            customers.Add(new Customer() { FirstName = "Jim", LastName = "Smith", Age = 23 });
            customers.Add(new Customer() { FirstName = "John", LastName = "Jones", Age = 22 });
            customers.Add(new Customer() { FirstName = "Sue", LastName = "Anders", Age = 21 });
            customers.Add(new Customer() { FirstName = "Chet", LastName = "Rogers", Age = 35 });
            customers.Add(new Customer() { FirstName = "James", LastName = "Anders", Age = 37 });
            return customers;
        }

    }
}

Answer 1

问题是CustomersViewModel .GetAll()是一种静态方法。绑定仅适用于实例属性。您应该将GetAll()的实现移动到构造函数，然后将该集合公开为该类的实例属性。

Answer 2

问题是，当CustomerViewModel中的GetAll是静态函数而不是实例属性时，您尝试绑定到CustomerViewModel.GetAll（）。

将静态函数更改为类似的内容（在CustomerViewModel中）：

public ObservableCollection<Customer> GetAll
{
    get { return Customer.GetAll(); }
}

为什么此View无法正确绑定到此ViewModel？

2 个答案: