DatePicker的绑定设置默认值1/1/0001 WPF C＃ [英] DatePicker databinding sets default value to 1/1/0001 WPF c#

问题描述

我有一个对象中绑定到DATATIME一个datepicker，并在运行时，而不是字符串选择日期中的DatePicker，1/1/0001表示，很难用实际日历。我没有当我用细绳捆绑的DatePicker问题，但将其更改为一个DateTime这样做。请让我知道如何工作的。这是我到目前为止有：

在XAML我有：

 <的DatePicker Grid.Column =4Grid.Row =9NAME =dueDateBoxVerticalAlignment =中心> 
< DatePicker.SelectedDate> 
<绑定路径=交货期UpdateSourceTrigger =的PropertyChanged模式=双向> 
< Binding.ValidationRules> 
<我：DateRangeRule /> 
< /Binding.ValidationRules> 
< /绑定> 
< /DatePicker.SelectedDate> 
< / DatePicker的> 
  

在C＃中我有：

 公众的DateTime DUEDATE 
 {
 {返回的dueDate; } 
组
 {
如果（DUEDATE！= NULL）|| ！DueDate.Equals（值））
 {
的dueDate =价值; 
 OnPropertyChanged（交货期）; 
} 
} 
} 
  

我也有一个依赖属性集，不知道这是否是扮演一个角色：

 公共静态只读的DependencyProperty DueDateProperty = 
 DependencyProperty.Register（交货期的typeof（DateTime的），
 typeof运算（UpdateJobDialog），新PropertyMetadata（DateTime.Now））; 
  

解决方案

可能会帮助使用日期时间？而不是日期时间，日期时间以来是不是空的，你设置的1/1/0001默认值，而不是零，这将导致该请你来约会的消息。

 公众的DateTime？ DUEDATE 
 {
 //需要改变私有变量的类型以及
 {返回的dueDate; } 
组
 {
如果（DUEDATE！= NULL）|| ！DueDate.Equals（值））
 {
的dueDate =价值; 
 OnPropertyChanged（交货期）; 
} 
} 
} 
  

I have a DatePicker bound to a DataTime within an object, and at run time, instead of the string "Select a Date" in DatePicker, "1/1/0001" is shown, making it hard to use the actual calendar. I did not have a problem when I was binding DatePicker with a string, but changing it to a DateTime did this. Please let me know how this works. This is what I have so far:

In XAML I have:

<DatePicker Grid.Column="4" Grid.Row="9" Name="dueDateBox" VerticalAlignment="Center">
    <DatePicker.SelectedDate>
        <Binding Path="DueDate" UpdateSourceTrigger="PropertyChanged" Mode="TwoWay">
            <Binding.ValidationRules>
                <my:DateRangeRule/>
            </Binding.ValidationRules>
        </Binding>
    </DatePicker.SelectedDate>
</DatePicker>

In the C# I have:

public DateTime DueDate
{
    get { return dueDate; }
    set
    {
        if (DueDate != null) || !DueDate.Equals(value))
        {
            dueDate = value;
            OnPropertyChanged("DueDate");
        }
    }
}

I also have a dependency property set, not sure if this is playing a part:

public static readonly DependencyProperty DueDateProperty =
        DependencyProperty.Register("DueDate", typeof(DateTime),
        typeof(UpdateJobDialog), new PropertyMetadata(DateTime.Now));

解决方案

Would probably help to use DateTime? instead of DateTime, since DateTime is not nullable, you are setting to the default value of 1/1/0001, rather than null which would result in the please select a date message you are used to.

public DateTime? DueDate
{
    //Need to change the type of the private variable as well
    get { return dueDate; }
    set
    {
        if (DueDate != null) || !DueDate.Equals(value))
        {
            dueDate = value;
            OnPropertyChanged("DueDate");
        }
    }
}

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