Question

TheContext指的是资源部分中的ViewModel

<DataGrid DataContext="{StaticResource TheContext}"
          ItemsSource="{Binding Path=Cars}">

这是我的viewModel.cs

public CarsSearchResultsViewModel()
{
     ButtonCommand = new DelegateCommand(x => GetCars());
}

public void GetCars()
{
     List<Car> cars = new List<Car>();
     cars.Add(new Car() { Make = "Chevy", Model = "Silverado" });
     cars.Add(new Car() { Make = "Honda", Model = "Accord" });
     cars.Add(new Car() { Make = "Mitsubishi", Model = "Galant" });
     Cars = new ObservableCollection<Car>(cars);
}

private ObservableCollection<Car> _cars;
public ObservableCollection<Car> Cars
{
     get { return _cars; }
     private set
     {
         if (_cars == value) return;
         _cars = value;
     }
}

我尝试添加OnPropertyChanged("Cars")，我尝试在添加列表之前添加People = null，我尝试将UpdateSourceTrigger=PropertyChanged添加到ItemsSource，在使用ObservableCollection之前我尝试使用{{ 1}}。

我没有尝试更新或删除集合，只需单击按钮填充网格即可。如果我在没有命令的构造函数中运行IViewCollection它可以正常工作。

Answer 1

您的ViewModel需要实现INotifyPropertyChanges界面，并在OnpropertyChanged的设置器中调用ObservableCollection，这样当您恢复用户界面时会收到通知，因此您的汽车属性应该看起来有些想法像这样：

private ObservableCollection<Car> _cars ;
    public ObservableCollection<Car> Cars
    {
        get
        {
            return _cars;
        }

        set
        {
            if (_cars == value)
            {
                return;
            }

            _cars = value;
            OnPropertyChanged();
        }
    }

需要在 TheContext 类中定义Cars集合，因为它是您的Context，最后一个需要实现上述接口：

public  class TheContext:INotifyPropertyChanged
{


    //Cars property and your code ..

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }
}

通过Button命令填充DataGrid

1 个答案: