UIElement.TransformToVisual(UIElement) 方法

参考

定义

命名空间:: Windows.UI.Xaml

重要

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编辑

返回一个转换对象，该对象可用于将坐标从 UIElement 转换为指定对象。

public:
 virtual GeneralTransform ^ TransformToVisual(UIElement ^ visual) = TransformToVisual;

GeneralTransform TransformToVisual(UIElement const& visual);

public GeneralTransform TransformToVisual(UIElement visual);

function transformToVisual(visual)

Public Function TransformToVisual (visual As UIElement) As GeneralTransform

参数

visual: UIElement

要与当前对象进行比较以获取转换的对象。如果此参数为 null，则使用 XAML 树的根。

GeneralTransform

作为对象的转换信息。对此对象调用方法以获取实际转换。

示例

此示例演示一个方案，用于调用 TransformToVisual 以解释不是事件发送方的元素的坐标参考框架中 PointerPoint 的坐标。在这里， queryPointer 方法首先访问与发送方相关的坐标， (这是方法) 第一行中的 GetCurrentPoint 调用，但稍后使用 TransformToVisual 将点坐标转换为布局容器的参考框架 page ，该容器实际上是 XAML 中的多个包含层。若要查看此代码 (的更多上下文，包括如何在 queryPointer UI 中显示结果以及何时) 调用它，请参阅处理指针输入主题中显示的完整代码示例。

    <Page
    x:Class="PointerInput.MainPage"
    IsTabStop="false"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:PointerInput"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Name="page">

    <Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="150" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="320" />
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Canvas Name="Container" 
                Grid.Column="0"
                Grid.Row="1"
                HorizontalAlignment="Center" 
                VerticalAlignment="Center" 
                Margin="0,0,0,0" 
                Height="320"  Width="640">
            <Rectangle Name="Target" 
                       Fill="#FF0000" 
                       Stroke="Black" 
                       StrokeThickness="0"
                       Height="320" Width="640" />
        </Canvas>
        <TextBox Name="eventLog" 
                 Grid.Column="1"
                 Grid.Row="0"
                 Grid.RowSpan="3" 
                 Background="#000000" 
                 TextWrapping="Wrap" 
                 Foreground="#FFFFFF" 
                 ScrollViewer.VerticalScrollBarVisibility="Visible" 
                 BorderThickness="0"/>
    </Grid>
</Page>

<Page
    x:Class="PointerInput.MainPage"
    IsTabStop="false"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:PointerInput"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Name="page">

    <Grid Background="{StaticResource ApplicationForegroundThemeBrush}">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="69.458" />
            <ColumnDefinition Width="80.542"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="320" />
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Canvas Name="Container" 
                Grid.Column="0"
                Grid.Row="1"
                HorizontalAlignment="Center" 
                VerticalAlignment="Center" 
                Margin="245,0" 
                Height="320"  Width="640">
            <Rectangle Name="Target" 
                       Fill="#FF0000" 
                       Stroke="Black" 
                       StrokeThickness="0"
                       Height="320" Width="640" />
        </Canvas>
        <Button Name="buttonClear"
                Foreground="White"
                Width="100"
                Height="100">
            clear
        </Button>
        <TextBox Name="eventLog" 
                 Grid.Column="1"
                 Grid.Row="0"
                 Grid.RowSpan="3" 
                 Background="#000000" 
                 TextWrapping="Wrap" 
                 Foreground="#FFFFFF" 
                 ScrollViewer.VerticalScrollBarVisibility="Visible" 
                 BorderThickness="0" Grid.ColumnSpan="2"/>
    </Grid>
</Page>

String queryPointer(PointerPoint ptrPt)
{
    String details = "";

    switch (ptrPt.PointerDevice.PointerDeviceType)
    {
        case Windows.Devices.Input.PointerDeviceType.Mouse:
            details += "\nPointer type: mouse";
            break;
        case Windows.Devices.Input.PointerDeviceType.Pen:
            details += "\nPointer type: pen";
            if (ptrPt.IsInContact)
            {
                details += "\nPressure: " + ptrPt.Properties.Pressure;
                details += "\nrotation: " + ptrPt.Properties.Orientation;
                details += "\nTilt X: " + ptrPt.Properties.XTilt;
                details += "\nTilt Y: " + ptrPt.Properties.YTilt;
                details += "\nBarrel button pressed: " + ptrPt.Properties.IsBarrelButtonPressed;
            }
            break;
        case Windows.Devices.Input.PointerDeviceType.Touch:
            details += "\nPointer type: touch";
            details += "\nrotation: " + ptrPt.Properties.Orientation;
            details += "\nTilt X: " + ptrPt.Properties.XTilt;
            details += "\nTilt Y: " + ptrPt.Properties.YTilt;
            break;
        default:
            details += "\nPointer type: n/a";
            break;
    }

    GeneralTransform gt = Target.TransformToVisual(page);
    Point screenPoint;

    screenPoint = gt.TransformPoint(new Point(ptrPt.Position.X, ptrPt.Position.Y));
    details += "\nPointer Id: " + ptrPt.PointerId.ToString() +
        "\nPointer location (parent): " + ptrPt.Position.X + ", " + ptrPt.Position.Y +
        "\nPointer location (screen): " + screenPoint.X + ", " + screenPoint.Y;
    return details;
}

String queryPointer(PointerPoint ptrPt)
{
    String details = "";

    switch (ptrPt.PointerDevice.PointerDeviceType)
    {
        case Windows.Devices.Input.PointerDeviceType.Mouse:
            details += "\nPointer type: mouse";
            break;
        case Windows.Devices.Input.PointerDeviceType.Pen:
            details += "\nPointer type: pen";
            if (ptrPt.IsInContact)
            {
                details += "\nPressure: " + ptrPt.Properties.Pressure;
                details += "\nrotation: " + ptrPt.Properties.Orientation;
                details += "\nTilt X: " + ptrPt.Properties.XTilt;
                details += "\nTilt Y: " + ptrPt.Properties.YTilt;
                details += "\nBarrel button pressed: " + ptrPt.Properties.IsBarrelButtonPressed;
            }
            break;
        case Windows.Devices.Input.PointerDeviceType.Touch:
            details += "\nPointer type: touch";
            details += "\nrotation: " + ptrPt.Properties.Orientation;
            details += "\nTilt X: " + ptrPt.Properties.XTilt;
            details += "\nTilt Y: " + ptrPt.Properties.YTilt;
            break;
        default:
            details += "\nPointer type: n/a";
            break;
    }

    GeneralTransform gt = Target.TransformToVisual(page);
    Point screenPoint;

    screenPoint = gt.TransformPoint(new Point(ptrPt.Position.X, ptrPt.Position.Y));
    details += "\nPointer Id: " + ptrPt.PointerId.ToString() +
        "\nPointer location (parent): " + ptrPt.Position.X + ", " + ptrPt.Position.Y +
        "\nPointer location (screen): " + screenPoint.X + ", " + screenPoint.Y;
    return details;
}

注解

调用 TransformToVisual 以获取 UI 中两个元素之间的坐标偏移量。要考虑的第一个元素是调用 TransformToVisual 的 UIElement，第二个元素是作为视觉参数传递的 UIElement。例如，可以使用转换来确定元素边界在相对于布局父元素（而不是应用窗口）的坐标系中的定位方式。

在应用了影响呈现和定位的所有注意事项（如 RenderTransform ）后，TransformToVisual 会提供坐标结果。如果要处理在 RenderTransform 动画或其他位置更改期间获取的点值，这非常有用。

TransformToVisual 最常见的方案是，如果要使用相对于调用它的 UIElement 的本地坐标系，并且未处理具有用于将 Point 值转换为对象的参照系的事件数据方法的实时输入事件。调用 TransformToVisual 后，可以对返回的 GeneralTransform 调用 TransformPoint。

注意

此方法返回的 GeneralTransform 对象可以强制转换为派生类型 Transform，但需要的所有方法均由 GeneralTransform 定义。无法强制转换为 TranslateTransform ，即使你可能希望转换结果为翻译。

适用于

通过

UIElement.TransformToVisual(UIElement) 方法

定义

参数

返回

示例

注解

适用于

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