Question

我正在使用TabControl创建一个WPF应用程序（UI），其中包含四个TabItem。 My Application - 从User Tab，我想以某种方式（可能带有复选框或任何其他方式）选择哪些GridColumns将显示在用户选项卡上。我可以使用其他标签，但有时我需要让用户有机会只使用他/她想要的特定输出。我怎样才能做到这一点？我是C＃和wpf的新手，所以如果你能解释一个简单的解决方案并提供一些代码，我会赞同它。

Answer 1

在回答你的问题之前，请给你一个简短的提示：当你提出要求时，发布一些代码，否则很难有人花时间帮助你。

要实施您的申请，您需要考虑：

ElementName data binding
ElementName数据绑定无法在ColumnDefinitions属性

要解决第2点，您可以阅读这个非常有趣的article by Josh Smith。

他实际上创造了一种特殊的ElementSpy附加属性：

public class ElementSpy : Freezable
{
    private DependencyObject element;

    public static ElementSpy GetNameScopeSource(DependencyObject obj)
    {
        return (ElementSpy)obj.GetValue(NameScopeSourceProperty);
    }

    public static void SetNameScopeSource(DependencyObject obj, ElementSpy value)
    {
        obj.SetValue(NameScopeSourceProperty, value);
    }

    public static readonly DependencyProperty NameScopeSourceProperty =
        DependencyProperty.RegisterAttached("NameScopeSource", typeof(ElementSpy), typeof(ElementSpy),
            new UIPropertyMetadata(null, OnNameScopeSourceProperty));

    private static void OnNameScopeSourceProperty(DependencyObject d, DependencyPropertyChangedEventArgs args)
    {
        INameScope nameScope;
        ElementSpy elementSpy = args.NewValue as ElementSpy;

        if (elementSpy != null && elementSpy.Element != null)
        {
            nameScope = NameScope.GetNameScope(elementSpy.Element);
            if (nameScope != null)
            {
                d.Dispatcher.BeginInvoke(new Action<DependencyObject, INameScope>(SetScope),
                    System.Windows.Threading.DispatcherPriority.Normal,
                    d, nameScope);
            }
        }
    }

    private static void SetScope(DependencyObject d, INameScope nameScope)
    {
        NameScope.SetNameScope(d, nameScope);
    }

    public DependencyObject Element
    {
        get
        {
            if (element == null)
            {
                PropertyInfo propertyInfo = typeof(Freezable).GetProperty("InheritanceContext",
                    BindingFlags.NonPublic | BindingFlags.Instance);

                element = propertyInfo.GetValue(this, null) as DependencyObject;

                if (element != null)
                {
                    Freeze();
                }
            }

            return element;
        }
    }

    protected override Freezable CreateInstanceCore()
    {
        return new ElementSpy();
    }
}

现在我们可以在XAML中使用绑定

<Window.Resources>
    <local:BooleanWidthConverter x:Key="BooleanWidthConverter" />
    <local:ElementSpy x:Key="ElementSpy" />
</Window.Resources>

    <StackPanel HorizontalAlignment="Stretch">
    <Grid local:ElementSpy.NameScopeSource="{StaticResource ElementSpy}"
            Margin="0,0,0,30">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="{Binding ElementName=cb1, Path=IsChecked, Converter={StaticResource BooleanWidthConverter}, Mode=OneWay}" />
            <ColumnDefinition Width="{Binding ElementName=cb2, Path=IsChecked, Converter={StaticResource BooleanWidthConverter}, Mode=OneWay}" />
            <ColumnDefinition Width="{Binding ElementName=cb3, Path=IsChecked, Converter={StaticResource BooleanWidthConverter}, Mode=OneWay}" />
        </Grid.ColumnDefinitions>

        <TextBlock HorizontalAlignment="Center" Text="Column 1" Margin="4" Grid.Column="0" />
        <TextBlock HorizontalAlignment="Center" Text="Column 2" Margin="4" Grid.Column="1" />
        <TextBlock HorizontalAlignment="Center" Text="Column 3" Margin="4" Grid.Column="2" />

    </Grid>

    <CheckBox x:Name="cb1" Content="Column 1" Margin="4" IsChecked="true" HorizontalAlignment="Center" />
    <CheckBox x:Name="cb2" Content="Column 2" Margin="4" IsChecked="true" HorizontalAlignment="Center" />
    <CheckBox x:Name="cb3" Content="Column 3" Margin="4" IsChecked="true" HorizontalAlignment="Center" />
</StackPanel>

要完成我们的代码，我们需要一个简单的转换器：

public class BooleanWidthConverter : IValueConverter
{
    private static GridLength star = new GridLength(1, GridUnitType.Star);
    private static GridLength zero = new GridLength(0, GridUnitType.Pixel);

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        bool boolValue = (bool)value;

        return boolValue ? star : zero;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

当然这只是一个示例原型，但我相信它可以帮助您完成应用程序。

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