CODEWITHSUNDEEP
wpfxamldata-bindingmvvmviewmodel
Edward Tanguay
Edward Tanguay

Reputation: 193432

Why is this View not correctly binding to this ViewModel?

I'm trying to bind my view to my view model without DataObjectProvider.

The following code runs without an error, but my ListBox is empty.

As far as I can tell, I correctly:

What little piece of syntax am I missing here?

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: (model)

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;
        }

    }
}

Upvotes: 1

Views: 382

Answers (2)

Josh G
Josh G

Reputation: 14256

The problem is that you are trying to bind to CustomerViewModel.GetAll(), when GetAll in CustomerViewModel is a static function not an instance property.

Change the static function to something like this (in CustomerViewModel):

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

Upvotes: 2

Andy
Andy

Reputation: 30418

The problem is that CustomersViewModel .GetAll() is a static method. Binding only works with instance properties. You should move the implementation of GetAll() to the constructor, and then expose the collection as an instance property of the class.

Upvotes: 2

Related Questions