如何使用 INotifyPropertyChanged 更新列表框

Question

我有一个日历，并且在日历项目控件中嵌套了一个项目控件，以便我可以在我想要为其创建事件的网格单元（日期）中显示事件。压延机为7列6行。现在我只是使用列表框来实际显示事件（标题）。我可以在启动时添加项目，但我希望能够在程序运行后添加/删除/更改。我以前尝试过 INotifyPropertyChanged 一次，但我一生都无法弄清楚。如果有人可以拿走我所拥有的东西并向我展示或给我如何做到这一点的提示，我将非常感激。

启动前我可以添加（项目）的类：

public class eventProperties : ObservableCollection<eventsTitles>
{
    //public string Eventer { get; set; }

    public eventProperties() : base() 
    {
        Add(new eventsTitles("First Test"));
        Add(new eventsTitles("First Test#2"));

    }

这是当程序启动并运行后我想添加事件时弹出的窗口（类）。我需要弄清楚如何使用此窗口添加项目以及如何将其添加到特定日期（gridcell）

    public Event(MainWindow parentform)
    {

        InitializeComponent();
        _parentForm = parentform;
        //this.month = month;
        //this.day = day;
        //this.year = year;
        lblCreateEvent.Content = "Create Event For " + month + " / " + day + " / " + year;

    }

    private void btnSubmit_Click(object sender, RoutedEventArgs e)
    {
        month = Convert.ToInt32(txtMonth.Text);
        day = Convert.ToInt32(txtDay.Text);
        year = Convert.ToInt32(txtYear.Text);



        Schedule sched = new Schedule();
        DateTime curr = DateTime.Now;
        int[] m = new int[7];
        DateTime newcurr = new DateTime(year, month, day);

        var cal = System.Globalization.DateTimeFormatInfo.CurrentInfo.Calendar;
        var ms = cal.GetWeekOfYear(new DateTime(newcurr.Year, newcurr.Month, 1), System.Globalization.CalendarWeekRule.FirstDay, System.DayOfWeek.Sunday);

           // for (var i = 1; newcurr.Month == 11; newcurr = newcurr.AddDays(1))
           // {

                var month_week = (newcurr.Day / 7);
                sched.MonthWeek = newcurr.GetWeekOfMonth().ToString();
                sched.Month = newcurr.Month.ToString();
                sched.Year = newcurr.Year.ToString();
                sched.day = newcurr.Day.ToString();
                sched.WeekOfYear = cal.GetWeekOfYear(newcurr, System.Globalization.CalendarWeekRule.FirstDay, DayOfWeek.Sunday).ToString();
                sched.dayofweek = newcurr.DayOfWeek.ToString();


                //Here is where the calender is created. By looping through all the days in the selected month it will find the weeknumber and day of the week -->
                // that that particular date belongs to and place in the correct gridcell.
                _parentForm.bindings.schedule.Add(new Schedule { WeekNo = newcurr.GetWeekOfMonth() - 1, WeekDay = (int)newcurr.DayOfWeek, day = newcurr.Day.ToString(), eventTitle = "Camper Calender"    });

这是实际的日历 XAML，我需要在其中绑定所有内容。

     </customgridcontrol:GridControl>


     </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <Button Content="{Binding day}" Width="175" HorizontalAlignment="Stretch" VerticalAlignment="Top" VerticalContentAlignment="Top" HorizontalContentAlignment="Left" Name="btnCalenderDate" Click="btnCalenderDate_Click" Loaded="btnCalenderDate_Loaded" Height="18" FontSize="10" FontWeight="Bold">
                        </Button>

                        <ItemsControl  Height="60" VerticalAlignment="Stretch">
                            <ItemsControl.Resources>
                                <src:eventProperties x:Key="dataList"/>
                            </ItemsControl.Resources>
                            <ItemsControl.Items>
                                <ListBox ItemsSource="{Binding Source= {StaticResource dataList} }" DisplayMemberPath="EventTitle" VerticalAlignment="Top" IsSynchronizedWithCurrentItem="True">            
                                </ListBox>
                            </ItemsControl.Items>
                        </ItemsControl>
                    </StackPanel>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
     <!-- ItemContainerStyle -->
        <ItemsControl.ItemContainerStyle>

            <Style >        
                    <Setter Property="Grid.Column" Value="{Binding WeekDay}"  />
                <Setter Property="Grid.Row" Value="{Binding WeekNo}" />
            </Style>
            </ItemsControl.ItemContainerStyle>
    </ItemsControl>

eventTitles 类

  namespace Camp_
  {
       public class eventsTitles
       {
            public string eventTitle {get; set;} 

            public eventsTitles()//String ev)
            {
               // this.eventTitle = ev;
            }

            public string EventTitle
            {
                get { return eventTitle; }
                set { eventTitle = value; }
            }
       }        
  }

Answer 1

Harsh 的答案对于您实施INotifyPropertyChanged 的​​方式是正确的，但是您只需要为单个属性实现它。如果您希望通知 UI Collection 已更改，请使用 ObservableCollection 类。

因此，如果您有一个包含 Event.EventTitle 的 Label，并且您想要更改在代码隐藏中的 EventTitle 中，您可以在 EventClass 上实现 INotifyPropertyChanged，以便在更新 myEvent.EventTitle 时UI 中的标签将自动更新为新值。

如果您有一个 ListBox（或 ItemsControl），并且希望在向集合添加项目或从集合中删除项目时自动更新，只需将 ListBox 绑定到 ObservableCollection 属性即可，当添加或删除项目时，它将自动更新 UI。

例如，

<ItemsControl.ItemTemplate>
    <DataTemplate>
        <StackPanel>
         <Button Content="{Binding day}" Click="AddEvent" />

         <ItemsControl Height="60" ItemsSource="{Binding Events}">
             <ItemsControl.ItemTemplate>
                 <DataTemplate>
                    <TextBlock Text="{Binding EventTitle}" />
                 <DataTemplate>
             </ItemsControl.ItemTemplate>
         </ItemsControl>
        </StackPanel>
    </DataTemplate>
</ItemsControl.ItemTemplate>

在此示例中，您的 Schedule 类将具有一个名为 Events 的属性，它是一个 ObservableCollection。要添加新事件，您可以使用如下内容：

void AddEvent(object sender, EventArgs e)
{
    // Get the DataContext for the Button, which should be of type Schedule
    Schedule day = (sender as Button).DataContext as Schedule;

    // Add New Event. Since this is an ObservableCollection, UI will automatically update
    day.Events.Add(new Event { EventTitle = "Test Event" });
}

作为旁注，您应该查看一些 .Net 命名约定

Answer 2

我认为 eventTitles 一定存在未实现 INotifyPropertyChanged 接口的问题，因此这里是实现的详细信息。

假设 eventTitles 类

public class eventTitles : INotifyPropertyChanged
{
    private string _eventtitle = string.Empty;

    public string EventTitle
    {
       get {return _eventtitle;}

        set
        {
            if (value != _eventtitle)
            {
                _eventtitle = value;
                NotifyPropertyChanged("EventTitle");
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }
}

如需进一步参考，您可以查看此 MSDN发布。