ObservableCollection不更新 [英] ObservableCollection not updating

问题描述

我觉得我真的很想让它开始工作.我有一个压光机，我希望用户能够从组合框中选择一个月并显示该日期的压光机.现在，无论我从组合框中选择什么，都不会显示任何内容.我可以通过使用列表框和按钮事件来使其正常工作，但是它并没有真正更新其内容，只是清除并显示所选的新月份.这不是正确的方法.我花了很多时间，如果有人可以看一下，也许给我一些建议，我将非常感激.

I feel like i'm really close to getting this to work. I have a calender, I want the user to be able to pick a month from a combobox and show the calender for that date. Right now nothing is being displayed no matter what I choose from the combobox. I can get it to work by using a listbox and a button event but its not really updating its just clearing and displaying the new month choosen. It's not the right way to do it. I've put a lot of time into this and if anybody can look at and maybe give me some pointers i'd really appreciate it.

--------模型类---------

--------Model Class---------

         public partial class SchedulePage : Page, INotifyPropertyChanged 
{
    public int pick2;
     public event PropertyChangedEventHandler PropertyChanged;
    MainWindow _parentForm;
    public int pick;
    Schedule sched = new Schedule();

    static GregorianCalendar _gc = new GregorianCalendar();


   public SchedulePage(MainWindow parentForm)
    {
        InitializeComponent();





    //    this.PropertyChanged += comboMonth_SelectionChanged;


        pick = Convert.ToInt32(comboMonth.SelectedItem);
        _parentForm = parentForm;



    }

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

    private int _nameofmonth ;

    public int NameofMonth
    {
        get
        {
            return this._nameofmonth;
        }

        set
        {
            if (value != this._nameofmonth)
            {
                this._nameofmonth = value;
                NotifyPropertyChanged("NameofMonth");
            }
        }
    }


 // void TheViewModel_PropertyChanged(object src, PropertyChangedEventArgs e)
    private void comboMonth_SelectionChanged(object sender, SelectionChangedEventArgs e)
  {
    //{

      //  if (e.PropertyName == "NameofMonth")
       // {
            //var date = new DateTime(2011, 11, 1);
            //makeCalender(date);

        _parentForm.bindings.schedule.Clear();
            var t = new List<Schedule>();
            DateTime curr = DateTime.Now;
            int jeez = comboMonth.SelectedIndex+1;
            //  comboMonth.Items.Add(curr.Month);
            DateTime newcurr = new DateTime(2011, NameofMonth+1, 1);
            //   pickdate = datePickercal.SelectedDate;
            //  DateTime newcurr = new DateTime(curr.Year, curr.Month, 1);
            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 == NameofMonth+1; 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();
                t.Add(sched);

                _parentForm.bindings.schedule.Add(new Schedule { WeekNo = newcurr.GetWeekOfMonth() - 1, WeekDay = (int)newcurr.DayOfWeek, day = newcurr.Day.ToString() });

            }
            lblDate.Content = (newcurr.Month - 1) + "/" + newcurr.Year;
            //testGrid.ItemsSource = t;
            comboMonth.DataContext = _parentForm.bindings;
            DataContext = _parentForm.bindings;

       // }

    }

---- XAML的一部分------

----Part of the XAML------

   <ComboBox  SelectedIndex="{Binding NameofMonth}" Grid.ColumnSpan="2" Height="23" HorizontalAlignment="Left" Margin="6,0,0,0" Name="comboMonth" VerticalAlignment="Top" Width="120" SelectionChanged="comboMonth_SelectionChanged">
            <ComboBoxItem Content="1" IsSelected="False" />
            <ComboBoxItem Content="2" />
            <ComboBoxItem Content="3" />
            <ComboBoxItem Content="4" />
            <ComboBoxItem Content="5" />
            <ComboBoxItem Content="6" />
            <ComboBoxItem Content="7" />
            <ComboBoxItem Content="8" />
            <ComboBoxItem Content="9" />
            <ComboBoxItem Content="10" />
            <ComboBoxItem Content="11" IsSelected="False" />
            <ComboBoxItem Content="12" />
        </ComboBox>

推荐答案

您需要使在ObservableCollection中使用的poco类实现INotifyChanged.

You need to make your poco class that is used within your ObservableCollection implement INotifyChanged.

示例:

<viewModels:LocationsViewModel x:Key="viewModel" />
.
.
.    
<ListView
    DataContext="{StaticResource viewModel}"
    ItemsSource="{Binding Locations}"
    IsItemClickEnabled="True"
    ItemClick="GroupSection_ItemClick"
    ContinuumNavigationTransitionInfo.ExitElementContainer="True">

    <ListView.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <TextBlock Text="{Binding Name}" Margin="0,0,10,0" Style="{ThemeResource ListViewItemTextBlockStyle}" />
                <TextBlock Text="{Binding Latitude, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Style="{ThemeResource ListViewItemTextBlockStyle}" Margin="0,0,5,0"/>
                <TextBlock Text="{Binding Longitude, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Style="{ThemeResource ListViewItemTextBlockStyle}" Margin="5,0,0,0" />
            </StackPanel>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

public class LocationViewModel : BaseViewModel
{
    ObservableCollection<Location> _locations = new ObservableCollection<Location>();
    public ObservableCollection<Location> Locations
    {
        get
        {
            return _locations;
        }
        set
        {
            if (_locations != value)
            {
                _locations = value;
                OnNotifyPropertyChanged();
            }
        }
    }
}

public class Location : BaseViewModel
{
    int _locationId = 0;
    public int LocationId
    {
        get
        {
            return _locationId;
        }
        set
        {
            if (_locationId != value)
            {
                _locationId = value;
                OnNotifyPropertyChanged();
            }
        }
    }

    string _name = null;
    public string Name
    {
        get
        {
            return _name;
        }
        set
        {
            if (_name != value)
            {
                _name = value;
                OnNotifyPropertyChanged();
            }
        }
    }

    float _latitude = 0;
    public float Latitude 
    { 
        get
        {
            return _latitude;
        }
        set
        {
            if (_latitude != value)
            {
                _latitude = value;
                OnNotifyPropertyChanged();
            }
        }
    }

    float _longitude = 0;
    public float Longitude
    {
        get
        {
            return _longitude;
        }
        set
        {
            if (_longitude != value)
            {
                _longitude = value;
                OnNotifyPropertyChanged();
            }
        }
    }
}

public class BaseViewModel : INotifyPropertyChanged
{
    #region Events
    public event PropertyChangedEventHandler PropertyChanged;
    #endregion

    protected void OnNotifyPropertyChanged([CallerMemberName] string memberName = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(memberName));
        }
    }
}

这篇关于ObservableCollection不更新的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！