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Accepted
Al John
Asked: 2024-06-02 19:51:30 +0800 CST

在 .NET MAUI 8 中从其自己的类中获取自定义控件的宽度？

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如何从自定义控件自己的类中获取其宽度？

我正在创建一个RangeSlider带有轨道、重叠范围和两个拇指来更改范围的自定义。在 中XAML，我可以RangeSlider通过绑定引用来获取自定义的宽度属性。就我自己而言，标签文本属性输出 352，这是RangeSlider.我想用这个宽度来进行计算，主要是确定范围的宽度以及两个拇指在这个范围端点的位置。

<ContentPage xmlns:controls="clr-namespace:NewProject1.Controls"
             ...
             .../>
    <VerticalStackLayout HorizontalOptions="Center"
                         VerticalOptions="Center">
        <Label Text="{Binding Source={x:Reference RangeSlider}, Path=Width}"/>
        <controls:RangeSlider x:Name="RangeSlider"/>
    </VerticalStackLayout>
</ContentPage>

如何从自定义控件RangeSlider类本身获取此宽度属性，例如，计算范围元素的宽度？

namespace NewProject1.Controls;

public class RangeSlider : ContentView {

    private Border Track = new Border
    {
        BackgroundColor = Colors.LightGray,
        StrokeThickness = 0,
        HeightRequest = 2,
        ZIndex = 1
    };

    private Border Range = new Border
    {
        BackgroundColor = Colors.DarkGray,
        StrokeThickness = 0,
        HeightRequest = 2,
        ZIndex = 2
    };

    private Border LeftThumb = new Border
    {
        BackgroundColor = Colors.Black,
        StrokeShape = new Ellipse(),
        StrokeThickness = 0,
        HeightRequest = 12,
        WidthRequest = 12,
        ZIndex = 3
    };

    private Border RightThumb = new Border
    {
        BackgroundColor = Colors.Black,
        StrokeShape = new Ellipse(),
        StrokeThickness = 0,
        HeightRequest = 12,
        WidthRequest = 12,
        ZIndex = 4
    };

    public RangeSlider()
    {
        this.Content = new Grid
        {
            Children =
            {
                Track,
                Range,
                LeftThumb,
                RightThumb
            },
            Padding = new Thickness(16, 3)
        };

        /**
         * My attempts to get the width of this custom control:
         */
        Range.WidthRequest = this.Width;
        Range.WidthRequest = this.Content.Width;
    }
    
    /**
     * Pan gesture handling...
     * Bindable properties...
     * etc. etc. etc.
     */
}

或者，如果适用，是否有更好的方法来计算仓位？

c#

1 个回答

  1. Best Answer

    创建构造函数时未计算宽度，因此我建议您使用OnSizeAllocated

    protected override void OnSizeAllocated(double width, double height)
{
    base.OnSizeAllocated(width, height);
    Range.WidthRequest = width;
}
    • 1

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