Xamarin-Local：PinchPanContainer未找到

Question

我无法找到我做错了。我有Picture.xaml页面，并且行<local:PinchPanContainer>行给出错误“找不到类型'local：PinchPanContainer'.....”这两个文件都位于“视图”文件夹中。

Picture.xaml：

<?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:GalShare.Views;assembly=GalShare" 
         x:Class="GalShare.Views.Picture">
<ContentPage.ToolbarItems>
    <ToolbarItem Text="Save to gallery" Order="Primary" Clicked="SaveToGal_Clicked"></ToolbarItem>        
</ContentPage.ToolbarItems>
<ContentPage.Content>
    <StackLayout>
        <ActivityIndicator BindingContext="{x:Reference MyImage}" IsRunning="{Binding IsLoading}"/>
        <local:PinchPanContainer>
            <local:PinchPanContainer.Content HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
              <Image x:Name="MyImage"  HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"/>
            </local:PinchPanContainer.Content>
        </local:PinchPanContainer>
    </StackLayout>
</ContentPage.Content>

PitchPanContainer.cs：

using System;
using Xamarin.Forms;
using Xamarin.Forms.Internals;

namespace GalShare.Views
{
public class PinchPanContainer : ContentView
{
    double currentScale = 1;
    double startScale = 1;
    double xOffset = 0;
    double yOffset = 0;
    bool blnDisableMove = false;

    public PinchPanContainer()
    {
        var pinchGesture = new PinchGestureRecognizer();
        pinchGesture.PinchUpdated += OnPinchUpdated;
        GestureRecognizers.Add(pinchGesture);

        var panGesture = new PanGestureRecognizer();
        panGesture.PanUpdated += OnPanUpdated;
        GestureRecognizers.Add(panGesture);
    }

    void OnPanUpdated(object sender, PanUpdatedEventArgs e)
    {
        if (Content.Scale == 1)
        {
            return;
        }

        switch (e.StatusType)
        {
            case GestureStatus.Running:

                if (!blnDisableMove)
                {
                    Content.TranslationX = Math.Max(Math.Min(0, xOffset + (e.TotalX * Scale)), -Math.Abs((Content.Width * Content.Scale) - Application.Current.MainPage.Width));
                    Content.TranslationY = Math.Max(Math.Min(0, yOffset + (e.TotalY * Scale)), -Math.Abs((Content.Height * Content.Scale) - Application.Current.MainPage.Height));
                }

                break;

            case GestureStatus.Completed:

                if (blnDisableMove)
                {
                    blnDisableMove = false;
                    return;
                }
                // Store the translation applied during the pan
                xOffset = Content.TranslationX;
                yOffset = Content.TranslationY;
                break;
        }
    }

    void OnPinchUpdated(object sender, PinchGestureUpdatedEventArgs e)
    {
        if (e.Status == GestureStatus.Started)
        {
            // Store the current scale factor applied to the wrapped user interface element,
            // and zero the components for the center point of the translate transform.
            startScale = Content.Scale;
            Content.AnchorX = 0;
            Content.AnchorY = 0;
            blnDisableMove = true;
        }
        if (e.Status == GestureStatus.Running)
        {
            // Calculate the scale factor to be applied.
            currentScale += (e.Scale - 1) * startScale;
            currentScale = Math.Max(1, currentScale);

            // The ScaleOrigin is in relative coordinates to the wrapped user interface element,
            // so get the X pixel coordinate.
            double renderedX = Content.X + xOffset;
            double deltaX = renderedX / Width;
            double deltaWidth = Width / (Content.Width * startScale);
            double originX = (e.ScaleOrigin.X - deltaX) * deltaWidth;

            // The ScaleOrigin is in relative coordinates to the wrapped user interface element,
            // so get the Y pixel coordinate.
            double renderedY = Content.Y + yOffset;
            double deltaY = renderedY / Height;
            double deltaHeight = Height / (Content.Height * startScale);
            double originY = (e.ScaleOrigin.Y - deltaY) * deltaHeight;

            // Calculate the transformed element pixel coordinates.
            double targetX = xOffset - (originX * Content.Width) * (currentScale - startScale);
            double targetY = yOffset - (originY * Content.Height) * (currentScale - startScale);

            // Apply translation based on the change in origin.
            Content.TranslationX = targetX.Clamp(-Content.Width * (currentScale - 1), 0);
            Content.TranslationY = targetY.Clamp(-Content.Height * (currentScale - 1), 0);

            // Apply scale factor.
            Content.Scale = currentScale;

            blnDisableMove = true;
        }
        if (e.Status == GestureStatus.Completed)
        {
            // Store the translation delta's of the wrapped user interface element.
            xOffset = Content.TranslationX;
            yOffset = Content.TranslationY;

            blnDisableMove = true;
        }
    }
}
}

我在做什么错？

Answer 1

不起作用的原因是您使用它的方式不正确，扩展选项不应位于Content属性上，而是在其上方用于声明布局的那一行，以下是您的容器的外观

  <local:PinchPanContainer HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
          <Image x:Name="MyImage"  HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"/>
    </local:PinchPanContainer>

此外，请注意Content属性是View的默认属性，因此它将直接将View的子级视为该属性的值。

此外，您的名称空间无需在视图同一程序集中使用它时就指定程序集！

   xmlns:local="clr-namespace:GalShare.Views" 

祝你好运

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