获取INotifyPropertyChanged类以返回List.Count

Question

I have the following class:

public partial class Operation : INotifyPropertyChanged
{
    private int tasks;

    public int Tasks
    {
        get
        {
            return this.tasks;
        }
        set
        {
            if (this.tasks != value)
            {
                this.tasks = value;
                this.OnPropretyChanged("Tasks");
            }
        }
    }

    protected virtual void OnPropretyChanged(string propertyName)
    {
        var handler = this.PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
 }

I then bind this class to dataGrid.DataSource and when ever Tasks variable change, it gets updated live in the datagrid. The problem is instead of int I need to use List where all the tasks are stored and I want Tasks to return List.Count instead of int tasks like this:

    public int Tasks
    {
        get
        {

            return this.TASKS.Count;
        }
        set
        {
            if (this.tasks != TASKS.Count)
            {
                this.tasks = TASKS.Count;
                this.OnPropretyChanged("Tasks");
            }
        }
    }

But dataGrid doesn't update automatically, I have to refresh it to see the update. Any suggestions how to handle this? Thanks!

Answer 1

List does not implement INotifyPropertyChanged or any other mechanism that lets you know when its contents are changed. You should use ObservableCollection<T> instead.