WPF 将 Width 绑定到 Parent.Width*0.3
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WPF binding Width to Parent.Width*0.3
提问by mandarin
I want to bind a control's Width to the parent's Width, but to a certain scale. Is there a way to do something like this:
我想将控件的宽度绑定到父级的宽度，但要绑定到一定的比例。有没有办法做这样的事情：
<Rectangle Name="rectangle1" Width="{Binding ActualWidth*0.3, ElementName=thumbnailCanvas, UpdateSourceTrigger=PropertyChanged}" Height="{Binding ActualHeight, ElementName=thumbnailCanvas, UpdateSourceTrigger=PropertyChanged}"/>
回答by Somedust
Sure, but you will need to use a converter. Something like this one:
当然可以，但您需要使用转换器。像这样的东西：
using System;
using System.Globalization;
using System.Windows.Data;
using System.Windows.Markup;
namespace WpfTestBench.Converters
{
public class PercentageConverter : MarkupExtension, IValueConverter
{
private static PercentageConverter _instance;
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return System.Convert.ToDouble(value) * System.Convert.ToDouble(parameter);
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
#endregion
public override object ProvideValue(IServiceProvider serviceProvider)
{
return _instance ?? (_instance = new PercentageConverter());
}
}
}
And your XAML will look like:
您的 XAML 将如下所示：
<Window x:Class="WpfTestBench.ScaleSample"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:converters="clr-namespace:WpfTestBench.Converters"
Title="Scale sample" Height="300" Width="300">
<Grid Name="ParentGrid">
<Rectangle
Width="{Binding Path=ActualWidth, ElementName=ParentGrid, Converter={converters:PercentageConverter}, ConverterParameter='0,5'}"
Stroke="Black" StrokeThickness="2" />
</Grid>
</Window>
回答by Garreye
I'd recommend simply doing this in XAML using a grid columns and the * width type:
我建议使用网格列和 * 宽度类型在 XAML 中简单地执行此操作：
<Window x:Class="NameSpace.WindowName"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="2*" />
</Grid.ColumnDefinitions>
<Grid Grid.Column="0"></Grid><!--This item take up 1/3 of window width-->
<Grid Grid.Column="1"></Grid> <!--This item take up remaining 2/3 of window width-->
</Grid>
</Window>
You can change the ratio of how much the columns take up by changing the numbers before the * in the column widths. Here it's setup as 1 and 2, so the grid will be split in 3 (sum of all * widths), with 1/3 of width to first column and 2/3 to second column.
您可以通过更改列宽中 * 之前的数字来更改列所占的比例。这里设置为 1 和 2，所以网格将被分成 3 个（所有 * 宽度的总和），第一列的宽度为 1/3，第二列的宽度为 2/3。
