15

我有一个绑定值，它返回一个 int，它表示我没有分配给元素左右边距的值。

这是我尝试过的，但它不会编译。

如果我设置整个边距，它会起作用，但我只想要左右。

xml:

<Image x:Name="_image" Source="mat.png" Margin="{Binding EditorRow.BondIndent},0,{Binding EditorRow.BondIndent},0" />

班级：

public int BondIndent
{
    get { return _bondSequence * 5; }
}
4

4 回答 4

29

退回保证金？

public Thickness Margin
{
    get { return new Thickness(BondIndent,0,BondIndent,0);}
}

然后改变：

<Image x:Name="_image" Source="mat.png" Margin="{Binding EditorRow.Margin}" />
于 2013-01-16T14:33:09.797 回答
15

您可能需要为此使用ValueConverter。就像是：

public class LeftRightThicknessConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is int)
        {
            int margin = (int)value;
            return Thickness(margin, 0, margin, 0);
        }
        return Thickness();
    }

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

然后，您可以通过以下方式使用转换器：

<Grid>
    <Grid.Resources>
        <xxx:LeftRightThicknessConverter x:Key="LeftRightThicknessConverter" />
    </Grid.Resources>

    <Image Margin="{Binding SomePropertyPath, Converter={StaticResource LeftRightThicknessConverter}}" />
</Grid>

假设这xxx是一个有效的 xml 命名空间。

于 2013-01-16T14:17:29.653 回答
2

int您可以返回一个Thickness ，而不是返回一个，它Margin实际上是：

public Thickness BondIndent
{
    get
    {
        int margin = _bondSequence * 5;
        return new Thickness(margin, 0, margin, 0);
    }
}

您的示例有效的原因是因为Thickness重载了带有 1、2 或 4 个参数的构造函数。当调用带有 1 个参数的构造函数时，所有边都被初始化为该值。WPF 会Thickness根据绑定值自动将其转换为 a。

在另一个主题上，BondIndent最好BondMargin还是BondThickness现在。

于 2013-01-17T10:20:02.153 回答
1

刚刚写了一些附加属性，应该可以很容易地从绑定或静态资源中设置单个 Margin 值：

WPF：

public class Margin
{
    public static readonly DependencyProperty LeftProperty = DependencyProperty.RegisterAttached(
        "Left",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0, LeftChanged));

    private static void LeftChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var frameworkElement = d as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;
            frameworkElement.Margin = new Thickness((double)e.NewValue, currentMargin.Top, currentMargin.Right, currentMargin.Bottom);
        }
    }

    public static void SetLeft(UIElement element, double value)
    {
        element.SetValue(LeftProperty, value);
    }

    public static double GetLeft(UIElement element)
    {
        return 0;
    }

    public static readonly DependencyProperty TopProperty = DependencyProperty.RegisterAttached(
        "Top",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0, TopChanged));

    private static void TopChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var frameworkElement = d as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;
            frameworkElement.Margin = new Thickness(currentMargin.Left, (double)e.NewValue, currentMargin.Right, currentMargin.Bottom);
        }
    }

    public static void SetTop(UIElement element, double value)
    {
        element.SetValue(TopProperty, value);
    }

    public static double GetTop(UIElement element)
    {
        return 0;
    }

    public static readonly DependencyProperty RightProperty = DependencyProperty.RegisterAttached(
        "Right",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0, RightChanged));

    private static void RightChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var frameworkElement = d as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;
            frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, (double)e.NewValue, currentMargin.Bottom);
        }
    }

    public static void SetRight(UIElement element, double value)
    {
        element.SetValue(RightProperty, value);
    }

    public static double GetRight(UIElement element)
    {
        return 0;
    }

    public static readonly DependencyProperty BottomProperty = DependencyProperty.RegisterAttached(
        "Bottom",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0, BottomChanged));

    private static void BottomChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var frameworkElement = d as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;
            frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, currentMargin.Right, (double)e.NewValue);
        }
    }

    public static void SetBottom(UIElement element, double value)
    {
        element.SetValue(BottomProperty, value);
    }

    public static double GetBottom(UIElement element)
    {
        return 0;
    }
}

超轻量级：

public class Margin
{
    public static readonly DependencyProperty LeftProperty = DependencyProperty.RegisterAttached(
        "Left",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0));

    public static void SetLeft(UIElement element, double value)
    {
        var frameworkElement = element as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;

            frameworkElement.Margin = new Thickness(value, currentMargin.Top, currentMargin.Right, currentMargin.Bottom);
        }
    }

    public static double GetLeft(UIElement element)
    {
        return 0;
    }

    public static readonly DependencyProperty TopProperty = DependencyProperty.RegisterAttached(
        "Top",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0));

    public static void SetTop(UIElement element, double value)
    {
        var frameworkElement = element as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;

            frameworkElement.Margin = new Thickness(currentMargin.Left, value, currentMargin.Right, currentMargin.Bottom);
        }
    }

    public static double GetTop(UIElement element)
    {
        return 0;
    }

    public static readonly DependencyProperty RightProperty = DependencyProperty.RegisterAttached(
        "Right",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0));

    public static void SetRight(UIElement element, double value)
    {
        var frameworkElement = element as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;

            frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, value, currentMargin.Bottom);
        }
    }

    public static double GetRight(UIElement element)
    {
        return 0;
    }

    public static readonly DependencyProperty BottomProperty = DependencyProperty.RegisterAttached(
        "Bottom",
        typeof(double),
        typeof(Margin),
        new PropertyMetadata(0.0));

    public static void SetBottom(UIElement element, double value)
    {
        var frameworkElement = element as FrameworkElement;
        if (frameworkElement != null)
        {
            Thickness currentMargin = frameworkElement.Margin;

            frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, currentMargin.Right, value);
        }
    }

    public static double GetBottom(UIElement element)
    {
        return 0;
    }
}

用法：

<TextBlock Text="Test"
    app:Margin.Top="{Binding MyValue}"
    app:Margin.Right="{StaticResource MyResource}"
    app:Margin.Bottom="20" />

好消息是它们不会覆盖 Margin 上的其他值，因此您也可以将它们组合起来。

于 2015-09-05T00:47:38.257 回答