Question

当DateTime？我的DateTimePicker控件的源更改为null，我想选择另一个日期，日历下拉默认为选定的上个月和年份。

我正在使用DateTimePicker进行DOB，因此月份和年份会有很大差异，我宁愿将日历重置为数据源更改为null时的当前月份和年份。来自WPFToolkit的DateTimePicker执行此操作，但我不想要它带有的微调器或时间选择，并且找不到隐藏它们的方法。

我正在使用MVVM设计模式，并希望避免立即代码隐藏。

来自视图的XAML：

<DatePicker Height="25" HorizontalAlignment="Left" Margin="53,47,0,0" 
    Name="dpEventDate" VerticalAlignment="Top" Width="115" 
    SelectedDate="{Binding EventItem.BirthDate, Mode=TwoWay, 
    UpdateSourceTrigger=PropertyChanged}" />

来自视图模型的C＃:(事件是我在模型中创建的类）

private Event _eventItem;

public event PropertyChangedEventHandler PropertyChanged;
public RelayCommand CreateCommand { get; private set; }

public Event EventItem
{
    get { return _eventItem; }
    set { _eventItem = value; OnPropertyChanged("EventItem"); }
}

public MainViewModel()
{
    EventItem = new Event();
    CreateCommand = new RelayCommand(CreateEvent);
}

protected void OnPropertyChanged(string name)
{
    PropertyChangedEventHandler handler = PropertyChanged;

    if (handler != null)
    {
        handler(this, new PropertyChangedEventArgs(name));
    }
}

如果我能提供更多细节来帮助您，请告诉我。

Answer 1

根据Adam的建议，以下是视图模型中的代码，它帮助我重置了DateTimePicker的日历显示：

private Event _eventItem;
private DateTime? _viewDate;

public event PropertyChangedEventHandler PropertyChanged;
public RelayCommand CreateCommand { get; private set; }

public Event EventItem
{
    get { return _eventItem; }
    set { _eventItem = value; OnPropertyChanged("EventItem"); }
}

// Decoy DateTime property
public DateTime? ViewDate
{
    get { return _viewDate; }
    set
    { 
        _viewDate = value;
        EventItem.EventDate = _viewDate; // Update the source

        OnPropertyChanged("ViewDate");
    }
}

public MainViewModel()
{
    EventItem = new Event();
    CreateCommand = new RelayCommand(CreateEvent);
}

private void CreateEvent()
{
    ViewDate = DateTime.Today; // Important for resetting the calendar display
    // Save input and set EventItem to new event for a clean slate
}

protected void OnPropertyChanged(string name)
{
    PropertyChangedEventHandler handler = PropertyChanged;

    if (handler != null)
    {
        handler(this, new PropertyChangedEventArgs(name));
    }

    // Important if you want your DatePicker control to be empty
    if(name.Equals("ViewDate") && DateTime.Today.Equals(ViewDate))
    {
        ViewDate = null;
    }
}

DateTimePicker日历默认为上个月/年选择

1 个答案: