Xamarin Forms向视图添加标记

Question

我的图像按钮有问题我希望我的功能Categorie_Onclick可以看到按钮被点击.我尝试添加标签,但它不起作用.有没有办法做到这一点？

XAML:

<!-- Button1 -->
<Image
  x:Name="CityGuideButton1"
  Source="shopping_gray.png"
  Aspect="Fill"
  HorizontalOptions="FillAndExpand"
  VerticalOptions ="FillAndExpand"
  Tag="01">
  <Image.GestureRecognizers>
    <TapGestureRecognizer
      Tapped="Categorie_Onclick"
      NumberOfTapsRequired="1"/>
  </Image.GestureRecognizers>
</Image>

<!-- Button2 -->
<Image
  x:Name="CityGuideButton2"
  Source="secrets.png"
  Aspect="Fill"
  HorizontalOptions="FillAndExpand"
  VerticalOptions ="FillAndExpand"
  Tag="02">
<Image.GestureRecognizers>
  <TapGestureRecognizer
    Tapped="Categorie_Onclick"
    NumberOfTapsRequired="1"/>
</Image.GestureRecognizers>

按钮处理程序

private async void Categorie_Onclick(Object sender, EventArgs args)
{
    Image cmd = sender as Image;
    string txt = TapGestureRecognizer.tag.ToString();
    await Navigation.PushAsync(new CategoriePage());
}

Answer 1

你可能会滥用StyleId,ClassId或者AutomationId为此,但这很糟糕,所以不要.

最简单的方法是定义一个附加的BindableProperty.您可以在所需的类中定义它.

public class Foo {
    public static readonly BindableProperty TagProperty = BindableProperty.Create("Tag", typeof(string), typeof(Foo), null);

    public static string GetTag(BindableObject bindable)
    {
        return (string)bindable.GetValue(TagProperty);
    }

    public static void SetTag(BindableObject bindable, string value)
    {
        bindable.SetValue(TagProperty, value);
    }
}

然后,您可以在Xaml中设置此标记

<Image ... local:Foo.Tag="button1" />

并从事件处理程序中获取该标记

async void Categorie_Onclick(Object sender, EventArgs args)
{
    Image cmd = sender as Image;
    string txt = Foo.GetTag(cmd);
    await Navigation.PushAsync(new CategoriePage());
}

您可能想知道为什么它没有内置到平台中.好吧,这可能是因为使用正确的Mvvm,这不是必需的.