的DateTimePicker WPF + + +绑定接受通过userinput DD / MM / YYYY [英] DateTimePicker + WPF + binding + accept dd/MM/yyyy via userinput

问题描述

简体问：

我在WPF一个datepicker。我在日期选择器的文本框中输入一个值30/10/1983。我需要被调回我的视图模型的价值，在那里我有它绑定到一个日期时间？属性。

I have a datepicker in WPF. I enter a value 30/10/1983 in the textbox of the datepicker. I need the value to be posted back to my viewmodel, where in I have bound it to a DateTime? property.

有什么办法，我可以做到这一点。毫米/ dd / yyyy格式触发回发，但不是DD / MM / YYYY。

Is there any way I can achieve this. mm/dd/yyyy format triggers a postback but not dd/mm/yyyy.

DatePicker的代码如下所示。

The DatePicker code is as below.

<DatePicker Grid.Row="2" Name="inputDate"
                Text="{Binding BirthDate,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                >

</DatePicker>

视图模型属性如下图所示。

The view model property is as below.

private DateTime? birthDate;

    public DateTime? BirthDate
    {
        get
        {
            return this.birthDate;
        }
        set
        {
            this.birthDate = value;
            OnPropertyChanged("BirthDate");
        }
    }

我输入一个值10/10到日期选择器的文本框，二传手被称为具有价值，但我输入整个日期30/10/1983的那一刻，我还是有它等于NULL视图模型属性。

I enter a value 10/10 into the datepicker textbox, the setter gets called with a value, but the moment I enter an entire date 30/10/1983, I still have the view model property which is equal to NULL.

我已经改变了格式，以英文UnitedKingdom的买家，在日历设置，我的CurrentCulture恰如其分地反映了EN-GB。

I have changed the Format to English-UnitedKingdom, in the calendar settings, and my CurrentCulture reflects en-GB appropriately.

原题：

我在WPF DateTimePicker控件，这是我已绑定视图模型中的文本属性设置为可空日期时间。

I have a datetimepicker control in WPF, which I have bound the text property to a Nullable DateTime in the view model.

我现在面临的问题是，当我的格式输入一个值MM / DD / YYYY，我做得到的视图模型值回传，表示新的价值。

The problem I am facing is when I enter a value in the format MM/dd/yyyy, I do get a value postback in the view model, indicating the new value.

但是，当我在DD输入值/ MM / YYYY格式，我没有得到通知在视图模型和值被丢失。中束缚propertyin视图模型为空

But when I enter the value in dd/MM/yyyy format, I do not get a notification in the view model and the value is lost. The bound propertyin the view model is null.

短日期格式是我在日历设置和放大器已指定的;日期格式，其内的短日期格式我公司提供的条目DD / MM / YYYY。

The short date format is the one which I have specified in the calendar settings & dateFormat, within which for a short date format I provide the entry as "dd/MM/yyyy".

可能有人请帮我这个场景，在我接受日期在DD / MM / YYYY格式，我不想硬编码，我想从日历设置拿起短日期格式，另外，我希望收到的视图模型更新的值了。

Could someone please help me with this scenario where in I accept date in dd/MM/yyyy format, and I do not want to hardcode, I wish to pick up the short date format from the calendar settings and also, I wish to recieve the updated value in the view model too.

推荐答案

的问题与一个无效的日期将不会设定一个正确的值您的视图模型的DateTime财产。所以，你可以拦截它，并正确地转换器转换

The problem is related that a not valid date will not set with a correct value your ViewModel DateTime property. So, you can intercept it and convert correctly with a CONVERTER.

一个例子：

public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        string strValue = System.Convert.ToString(value);
        DateTime resultDateTime;
        if (DateTime.TryParse(strValue, out resultDateTime))
        {
            return resultDateTime;
        }
        return value;    
    }

和您的XAML代码将是这样的：

And your XAML code will be like:

 <DatePicker 
     Text="{Binding BirthDate,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
     SelectedDate="{Binding RelativeSource={RelativeSource Self},Path=Text,
     Converter={StaticResource DateConverter}}"
  />

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