值为null或不为null时，如何在列表视图中选中复选框？

Question

I am creating a WPF ListView with multiple GridViewColumn s and would like to set a CheckBox IsChecked property to true or false based on a binding and whether or not that data value is null or not null.

I tried using a DataTrigger below to accomplish this but it doesn't seem to be working. It basically keeps everything unchecked in the ListView .

<GridViewColumn Header="W()" Width="20" >
    <GridViewColumn.CellTemplate>
        <DataTemplate>
            <CheckBox Content="Tell me something" >
                <CheckBox.Style>
                    <Style TargetType="{x:Type CheckBox}">
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding WebsiteJob}" Value="{x:Null}">
                                <Setter Property="IsChecked" Value="False" />
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </CheckBox.Style>
            </CheckBox>
        </DataTemplate>
    </GridViewColumn.CellTemplate>
</GridViewColumn>

Is there a way for me to handle specific columns in a ListView with GridViewColumn based on their binding? Truly in this situation I want to supply the CheckBox with some custom content as well as set it to IsChecked. I am pretty new to WPF so be easy.

Answer 1

Ok here is what I did based on the advice in the question comments. I created an IValueConverter which stores the original object. This allows me to perform all kinds of validation on the nested object itself and then set it back when its done.

public class CheckboxIsCheckedValueConverter : IValueConverter {

    public object OriginalValue;

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture) {
        if (value != null) {
            OriginalValue = value;
            return true;
        }
        return false;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) {
        if ((bool)value == true) {
            return OriginalValue;
        } else {
            return null;
        }
    }
}

Also, I had to change the xaml import to the following below. Even though x:Shared doesn't popup in Intellisense it still does exist. This makes sure that each instance of the converter is unique and allows me to store the original value.

<l:CheckboxIsCheckedValueConverter x:Key="CheckboxIsCheckedValueConverter" x:Shared="False" />

Modified GridViewColumn

<GridViewColumn HeaderContainerStyle="{StaticResource SmokeStyleHeaders}" Header="W()" Width="30" >
    <GridViewColumn.CellTemplate>
        <DataTemplate>
            <CheckBox Foreground="White" Checked="CheckBox_Checked" IsChecked="{Binding WebsiteJob, Converter={StaticResource CheckboxIsCheckedValueConverter}}" Content="{Binding WebsiteJob, Converter={StaticResource WebsiteJobValueConverter}}" />
        </DataTemplate>
    </GridViewColumn.CellTemplate>
</GridViewColumn>