WPF绑定问题

我有一个目标:

    class a 
    { 
        public string Application; 
        public DateTime From, To;
    }

我在此声明:

    ObservableCollection<a> ApplicationsCollection = 
        new ObservableCollection<a>();

在我的XAML中,我有:

    <ListView Height="226.381" Name="lstStatus" Width="248.383" HorizontalAlignment="Left" Margin="12,0,0,12" VerticalAlignment=">
        <ListView.View>
            <GridView>
                <GridViewColumn Width="140" Header="Application"
                                DisplayMemberBinding="{Binding Path=Application}"/>
                <GridViewColumn Width="50" Header="From" 
                                DisplayMemberBinding="{Binding Path=From}"/>
                <GridViewColumn Width="50" Header="To" 
                                DisplayMemberBinding="{Binding Path=To}"/>
            </GridView>
        </ListView.View>
    </ListView>

当我这样做时:

        lstStatus.ItemsSource = ApplicationsCollection;

我收到一堆错误,但在我的列表视图中没有显示任何内容:

System.Windows.Data Error: 39 : BindingExpression path error: 'Application' property not found on 'object' ''a' (HashCode=60325168)'. BindingExpression:Path=Application; DataItem='a' (HashCode=60325168); target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String')
System.Windows.Data Error: 39 : BindingExpression path error: 'From' property not found on 'object' ''a' (HashCode=60325168)'. BindingExpression:Path=From; DataItem='a' (HashCode=60325168); target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String')
System.Windows.Data Error: 39 : BindingExpression path error: 'To' property not found on 'object' ''a' (HashCode=60325168)'. BindingExpression:Path=To; DataItem='a' (HashCode=60325168); target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String')

a a的属性显然是正确的,为什么这不起作用呢?