如何在类型为DateTime的属性中将空白设置为默认值？

Question

我已经创建了一个DateTime类型的属性。当我在InvokePropertyChanged（）事件的标签上设置此属性值时，它显示默认值（1/1/0001 12:00:00）。如果属性没有有效日期，我如何设置空白文本？

public event PropertyChangedEventHandler PropertyChanged; 
private DateTime? _dDateTime = null; 

public DateTime PostedDateTime 
{ 
    get 
    { 
     return _dDateTime.HasValue ? _dDateTime.Value : DateTime.Now; 
    } 
    set 
    { 
     _dDateTime = value; 
     InvokePropertyChanged(new PropertyChangedEventArgs("PostedDateTime")); 
    } 
} 

public void InvokePropertyChanged(PropertyChangedEventArgs e) 
{ 
    PropertyChangedEventHandler handler = PropertyChanged; 
    if (handler != null) 
    { 
     handler(this, e); 
     Refresh(); 
    } 

    if (e.PropertyName.Equals("PostedDateTime")) 
     lblDateTimeDt.Text = PostedDateTime.ToString();// setting datetime in label 

} 

Answer 1

可以assgin之前测试值

public void InvokePropertyChanged(PropertyChangedEventArgs e) 
{ 
    PropertyChangedEventHandler handler = PropertyChanged; 
    if (handler != null) 
    { 
     handler(this, e); 
     Refresh(); 
    } 

    if (e.PropertyName.Equals("PostedDateTime")) 
    lblDateTimeDt.Text = PostedDateTime == DateTime.MinValue ? "" : PostedDateTime.ToString(); 

}