仅绑定 WPF 控件的部分边距属性 [英] Binding only part of the margin property of WPF control

问题描述

我有这个:

<TabControl Margin="0,24,0,0">...</TabControl>

我只想绑定 TabControl 的 "Top" 部分，直觉上我会这样做:

I want to bind only the "Top" part of the TabControl, which intuitively I would do it this way:

<TabControl Margin="0,{Binding ElementName=TheMenu, Path=Height},0,0">
 ...
</TabControl>

我该怎么做?

推荐答案

您是否尝试过使用这样的转换器?

Have you tried using a converter like this?

在 VB.Net

Public Class MarginConverter
  Implements IValueConverter

  Public Function Convert(ByVal value As Object, ByVal targetType As System.Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IValueConverter.Convert
    Return New Thickness(0, CDbl(value), 0, 0)
  End Function

  Public Function ConvertBack(ByVal value As Object, ByVal targetType As System.Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IValueConverter.ConvertBack
    Return Nothing
  End Function
End Class

或在 C# 中

public class MarginConverter : IValueConverter
{

    public object Convert(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return new Thickness(0, System.Convert.ToDouble(value), 0, 0);
    }

    public object ConvertBack(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return null;
    }
}

XAML

<Window.Resources>
    <local:MarginConverter x:Key="marginConverter"></local:MarginConverter>
</Window.Resources>
<Grid>
    <StackPanel>
        <Slider Name="Slider1"></Slider>
        <TabControl Name="TabControl" Margin="{Binding ElementName=Slider1, Path=Value, Converter={StaticResource marginConverter}}">
            <Button>Some content</Button>
        </TabControl>
    </StackPanel>
</Grid>

使用多功能转换器

还可以在运行时获取所有四个值并使用 MultiValueConverter.厚度对象的顶级属性不是依赖对象，因此您不能定义到它的绑定(除非您的源不是依赖对象).

It is also possible to get all four values during run-time and use a MultiValueConverter. The Top-Property of the Thickness-Object is not a Dependency-Object, therefor you can't define a binding to it (unless your source is not a Dependency-Object).

XAML

<Window.Resources>
    <local:MarginConverter x:Key="marginConverter"></local:MarginConverter>
    <local:MultiMarginConverter x:Key="multiMarginConverter"></local:MultiMarginConverter>
</Window.Resources>
<Grid>
    <StackPanel>
        <Slider Name="Slider1"></Slider>
        <Slider Name="Slider2"></Slider>
        <Slider Name="Slider3"></Slider>
        <Slider Name="Slider4"></Slider>
        <TabControl Name="TabControl">
            <TabControl.Margin>
                <MultiBinding Converter="{StaticResource multiMarginConverter}">
                    <Binding ElementName="Slider1" Path="Value"></Binding>
                    <Binding ElementName="Slider2" Path="Value"></Binding>
                    <Binding ElementName="Slider3" Path="Value"></Binding>
                    <Binding ElementName="Slider4" Path="Value"></Binding>
                </MultiBinding>
            </TabControl.Margin>
            <Button>Some content</Button>
        </TabControl>
    </StackPanel>
</Grid>

... 和 c#

  class MultiMarginConverter : IMultiValueConverter
  {
    public object Convert(object[] values, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
      return new Thickness(System.Convert.ToDouble(values[0]),
                           System.Convert.ToDouble(values[1]),
                           System.Convert.ToDouble(values[2]),
                           System.Convert.ToDouble(values[3]));
    }

    public object[] ConvertBack(object value, System.Type[] targetType, object parameter, System.Globalization.CultureInfo culture)
    {
      return null;
    }
  }

编辑(2) 反向绑定:
我不确定这是否会让你开心.以我的拙见，我会尽量避免这种情况，但是好吧...如果您的来源是依赖属性，您可以将其绑定到边距:

Edit(2) Reverse-Binding:
I'm not sure if this will make you happy. In my humble opinion I would try to avoid this, but ok... If your source is a Dependency-Property, you can bind this to the Margin:

<Slider Name="Slider5" Minimum="-99" Maximum="0" Value="{Binding ElementName=TabControl, Path=Margin.Top, Mode=OneWayToSource}"></Slider>

但我对此有一些影响.
诀窍是，您不将 TabControl 的 Margin 的一部分绑定到其他东西"，而是将其他东西"绑定到 TabControl 的 Margin 并指定绑定模式 OneWayToSource.

But I've got some effects with this.
The trick is, that you do not bind a part of the Margin of your TabControl to "something else", but bind "something else" to the Margin of your TabControl and specify Binding-Mode OneWayToSource.

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