DataTrigger 在选中 RadioButton 时更新 DatePicker

Question

我只是想根据单选按钮的 IsChecked 在 DatePicker 中设置 SelectedDate。当单选按钮 IsChecked 为真时，应在 DatePicker 中输入今天的日期。如果 IsChecked 为假，则 DatePicker 应为空。我已经尝试了数据触发器的各种再现，但 none 已经产生了任何好处。无论单选按钮是什么，DatePicker 中都不会填充任何内容。我缺少什么才能让它正常工作？

<DatePicker Grid.Row="19" Grid.Column="1" Width="120" SelectedDate="{Binding SelectedApplication.DateHireDeclineSent}"
            Visibility="{Binding IsChecked, ElementName=HireDeclinedYes, Converter={StaticResource BooleanToVisibilityConverter}}" >
    <DatePicker.Style>
        <Style TargetType="DatePicker">                                    
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=HireDeclinedYes, Path=IsChecked, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Value="True">
                    <Setter Property="SelectedDate" Value="{x:Static sys:DateTime.Now}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding ElementName=HireDeclinedYes, Path=IsChecked}" Value="False">
                    <Setter Property="SelectedDate" Value="{x:Null}"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DatePicker.Style>
</DatePicker>

<StackPanel Grid.Row="16" Grid.Column="4" Orientation="Horizontal"
            Visibility="{Binding IsChecked,ElementName=NoHireAdd, Converter={StaticResource BooleanToVisibilityConverter}}">
    <RadioButton x:Name="HireDeclinedYes" Content="Yes" IsChecked="{Binding SelectedApplication.HireDeclined}" />
    <RadioButton x:Name="HireDeclinedNo" Margin="5,0,0,0" Content="No" IsChecked="{Binding SelectedApplication.HireDeclined, Converter={StaticResource BoolInverterConverter}}" />
</StackPanel>

Answer 1

由于 DatePicker SelectedDate 绑定到 SelectedApplication.DateHireDeclineSent 并且单选按钮 IsChecked 属性绑定到SelectedApplication.HireDeclined ，您可以在 SelectedApplication.HireDeclined 的 setter 中也更改 SelectedApplication.DateHireDeclineSent 属性并提高属性更改事件？

这将更改绑定到 DatePicker 的属性，属性 changed 事件将通知视图有关更改，从而更改 DatePicker SelectedDate。

就像这样：

private bool _hireDeclined;
public bool HireDeclined
{
    get => _hireDeclined;
    set 
    {
        _hireDeclined = value;
        NotifyPropertyChanged("HireDeclined");
        if (//some condition)
            DateHireDeclineSent = DateTime.Now;
    }
}

private DateTime _dateHireDeclineSent;
public DateTime DateHireDeclineSent
{
    get => _dateHireDeclineSent;
    set
    {
        _dateHireDeclineSent = value;
        NotifyPropertyChanged("DateHireDeclineSent");
    }
}

Answer 2

如果您删除 SelectedDate="{Binding SelectedApplication.DateHireDeclineSent}" 并使用 setter:

设置默认值，它应该可以工作

<DatePicker Grid.Row="19" Grid.Column="1" Width="120"
            Visibility="{Binding IsChecked, ElementName=HireDeclinedYes, Converter={StaticResource BooleanToVisibilityConverter}}" >
    <DatePicker.Style>
        <Style TargetType="DatePicker">
            <Setter Property="SelectedDate" Value="{Binding SelectedApplication.DateHireDeclineSent}" />
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=HireDeclinedYes, Path=IsChecked, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Value="True">
                    <Setter Property="SelectedDate" Value="{x:Static sys:DateTime.Now}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding ElementName=HireDeclinedYes, Path=IsChecked}" Value="False">
                    <Setter Property="SelectedDate" Value="{x:Null}"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DatePicker.Style>
</DatePicker>

本地值优先于样式 setters：https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/dependency-property-value-precedence

DataTrigger 在选中 RadioButton 时更新 DatePicker

DataTrigger to Update a DatePicker when a RadioButton IsChecked

c#

wpf

datatrigger