Question

我为这个奇怪的主题措辞道歉。

我有两个日期选择器，一个仅接受数值的Duration文本框，以及SelectedDateChanged的两个方法以及Text_TextChanged。

我想要做的是MS Project用他们的开始日期/结束日期/持续时间做什么（如果有人对它有任何了解）但基本上，用户可以输入3中的2个，它将填充其他一个相应的。因此，如果我在文本框中输入3（天）并且在我的结束日期DatePicker中选择12/10/2013，则我的2个对象应该说是startdate - 12/10/2013结束日期 - 12/13/2013文本3 < / p>

这是我的2个datePicker方法背后的代码。

    private void DatePickerEndDate1_SelectedDateChanged(object sender, SelectionChangedEventArgs e)
    {
        if(!String.IsNullOrWhiteSpace(DatePickerEndDate1.ToString()))
            newEndDate = DateTime.Parse(DatePickerEndDate1.ToString());
        if (!String.IsNullOrWhiteSpace(DatePickerEndDate1.ToString()) && !String.IsNullOrWhiteSpace(DatePickerStartDate1.ToString()))
        {
            if (DatePickerEndDate1.SelectedDate < DatePickerStartDate1.SelectedDate)
            {
                DatePickerStartDate1.SelectedDate = DatePickerEndDate1.SelectedDate;
                DatePickerEndDate1.SelectedDate = originalStartDate;
            }

            TimeSpan differenceBetweenStartandEndDate = newEndDate.Subtract(newStartDate);
            TextDuration.Text = differenceBetweenStartandEndDate.Days.ToString();
        }
        else if (DatePickerEndDate1.SelectedDate != null && DatePickerStartDate1.SelectedDate == null)
        {
            DatePickerStartDate1.SelectedDate = newEndDate;
            DatePickerEndDate1.SelectedDate = newEndDate.AddDays(taskLength);
        }
    }

    private void DatePickerStartDate1_SelectedDateChanged(object sender, SelectionChangedEventArgs e)
    {
        if(!String.IsNullOrWhiteSpace(DatePickerStartDate1.ToString()))
            newStartDate = DateTime.Parse(DatePickerStartDate1.ToString());
        if (!String.IsNullOrWhiteSpace(DatePickerEndDate1.ToString()) && !String.IsNullOrWhiteSpace(DatePickerStartDate1.ToString()))
        {
            if (DatePickerStartDate1.SelectedDate > DatePickerEndDate1.SelectedDate)
            {
                DatePickerEndDate1.SelectedDate = DatePickerStartDate1.SelectedDate;
                DatePickerStartDate1.SelectedDate = originalEndDate;
            }


            TimeSpan differenceBetweenStartandEndDate = newEndDate.Subtract(newStartDate);
            TextDuration.Text = differenceBetweenStartandEndDate.Days.ToString();
        }
        else if (DatePickerStartDate1.SelectedDate != null && DatePickerEndDate1.SelectedDate == null)
        {
            DatePickerEndDate1.SelectedDate = newEndDate;
            DatePickerStartDate1.SelectedDate = newEndDate.AddDays(taskLength);
        }

    }

我正在调试并意识到我的错误来自于我在Else if方法中重置说DatePickerStartDate1（对于此实例）。这将改变我的DatePickerEndDate1，因为它被更改，这也将调用我的TextDuration_TextChanged。

    private void TextDuration_TextChanged(object sender, TextChangedEventArgs e)
    {
        if(int.TryParse(TextDuration.Text, out taskLength))

        if (DatePickerStartDate1.SelectedDate != null)
        {
            DatePickerEndDate1.SelectedDate = newStartDate.AddDays(taskLength);
        }
        else if (DatePickerEndDate1.SelectedDate != null)
        {
            DatePickerStartDate1.SelectedDate = newEndDate.AddDays(taskLength);
        }
    }

正在解雇它，它会将我的taskLength重置为0并最终将所有日期设置为12/10/2013，因为它从未添加3天。

现在我想知道我是否可以编写一行不会调用该方法的代码，当且仅当我在其他地方时才这样做？

Answer 1

您正试图在用户界面中执行业务逻辑，这很麻烦如果您使用日期选择器以外的其他内容更改日期，不仅会发生混乱，而且会失败 Binding，get，set和NotifyPropertyChanged是你的朋友

private DateTime? date1;
private DateTime? date2;
private Int32? taskLength;

public DateTime? Date1
{
    get { return date1; }
    set 
    {
        if (date1 == value) return;
        date1 = value;
        NotifyPropertyChanged("Date1");
        if (taskLength != null && date1 != null)
        {  
            date2 = date1.AddDays(taskLength);  
            // by calling the backing property you don't hit the set 
            NotifyPropertyChanged("Date2");
            // anything bound will call the get 
        }
    }
}

Answer 2

我过去处理这个问题的方法是使用“忽略事件”标志。代码看起来像这样：

public class MyForm
{
   private bool _disableEvents = false;

   private void Event1(object sender, EventArgs e)
   {
      if (_disableEvents)
         return;

      _disableEvents = true;
      try
      {
         // do stuff that triggers Event2
      }
      finally
      {
         _disableEvents = false;
      }
   }

   private void Event2(object sender, EventArgs e)
   {
      if (_disableEvents)
         return;

      _disableEvents = true;
      try
      {
         // do stuff that triggers Event1
      }
      finally
      {
         _disableEvents = false;
      }
   }
}

覆盖方法调用，以便在特定情况下不调用它

2 个答案: