c# - 如何从 C# 代码获取屏幕大小到 XAML？

Question

我知道如何从代码中获取屏幕尺寸。但是我怎样才能将这些数字传递给 XAML 以便我可以正确地绘制屏幕呢？我正在尝试制作一个包含 3 行的基本网格。中间的高度应与设备屏幕宽度相同。我现在拥有的是:

<Grid BackgroundColor="Black">
    <Grid.RowDefinitions>
        <RowDefinition Height="*" />
        <RowDefinition Height="I DONT KNOW WHAT TO PUT HERE :S" />
        <RowDefinition Height="*" />
    </Grid.RowDefinitions>
    <Grid Grid.Row="1" BackgroundColor="Blue" Margin="10" />
</Grid>

对我来说，这似乎是一件非常基本的事情，但我找不到任何关于如何做到这一点的例子。

Answer 1

您可以通过Xamarin.Essentials: Device Display Information获取设备信息，创建一个名为 Constant 的结构，并在其中定义 ScreenWidth 和 ScreenHeight。

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();

        // Get Metrics
        var mainDisplayInfo = DeviceDisplay.MainDisplayInfo;

        // Orientation (Landscape, Portrait, Square, Unknown)
        var orientation = mainDisplayInfo.Orientation;

        // Rotation (0, 90, 180, 270)
        var rotation = mainDisplayInfo.Rotation;

        // Width (in pixels)
        var width = mainDisplayInfo.Width;

        // Height (in pixels)
        var height = mainDisplayInfo.Height;

        // Screen density
        var density = mainDisplayInfo.Density;

    }
}

public struct Constant
{
    public static double ScreenWidth = DeviceDisplay.MainDisplayInfo.Width / DeviceDisplay.MainDisplayInfo.Density;
    public static double ScreenHeight = DeviceDisplay.MainDisplayInfo.Height / DeviceDisplay.MainDisplayInfo.Density;
}

在xaml中使用它:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:d="http://xamarin.com/schemas/2014/forms/design"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d"
             xmlns:local="clr-namespace:App105"
             x:Class="App105.MainPage">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="{Binding Source={x:Static local:Constant.ScreenWidth}}" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Label Text="Top Left" BackgroundColor="Red" Grid.Row="0" Grid.Column="0" />
        <Label Text="Top Right" BackgroundColor="Blue" Grid.Row="0" Grid.Column="1" />
        <Label Text="middle Left" BackgroundColor="Green" Grid.Row="1" Grid.Column="0" />
        <Label Text="middle Right" BackgroundColor="Yellow" Grid.Row="1" Grid.Column="1" />
        <Label Text="Bottom Left" BackgroundColor="Orange" Grid.Row="2" Grid.Column="0" />
        <Label Text="Bottom Righ" BackgroundColor="Pink" Grid.Row="2" Grid.Column="1" />
    </Grid>

</ContentPage>