UserControl能不能自定义事件？

Question

例如，我在一个UserControl控件UC1中添加了一个按钮B1，希望按下按钮后触发UC1的事件，能不能办到？

1. 如果能，怎么办？
2. 如果不能，能不能从外界访问UserControl里的全局变量？

我原来的想法是：通过按下B1通知外界将UC1删除，但是似乎需要事件才能办到。

Answer 1

你好，当然可以，我这里用C#写了一个，可以作为参考，原理很简单，点击B1的时候传出一个信号给主页面，主页面通过信号来删除当前UserControl：

首先是你的UserControl，我在里面画了一个Button用来被点击：

<UserControl
    x:Class="App97.MyUserControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App97"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300"
    d:DesignWidth="400">

    <Grid>
        <Button Content="Button" HorizontalAlignment="Left" Height="112" Margin="136,87,0,0" VerticalAlignment="Top" Width="127" Click="Button_Click"/>

    </Grid>
</UserControl>

这一段是UserControl的后台代码，首先我需要注册一个Dependency Property，这样才可以把是否删除的信号传出去，这里我定义了一个Deletable的值，如果是False的话是不可删除，如果是True的话是可删除。

    public sealed partial class MyUserControl1 : UserControl
    {
        public MyUserControl1()
        {
            this.InitializeComponent();
        }


        public static readonly DependencyProperty SpeciesProperty =
            DependencyProperty.Register(
            "Deletable",
            typeof(Boolean),
            typeof(Boolean), null
            );
        public Boolean Deletable
        {
            get { return (Boolean)GetValue(SpeciesProperty); }
            set { SetValue(SpeciesProperty, (Boolean)value); }
        }


        private void Button_Click(object sender, RoutedEventArgs e)
        {
            Deletable = true;
        }
    }

XAML放置进去：

<Page
    x:Class="App97.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App97"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <StackPanel x:Name="stp">
            <local:MyUserControl1 x:Name="mycontrol"></local:MyUserControl1>
        </StackPanel>
    </Grid>
</Page>

下面这一段是后台代码，主要功能是通过监听UserControl的Deletable属性来看是否可以把UserControl删除：

    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();

            DispatcherTimer timer = new DispatcherTimer();
            timer.Tick += timer_tick;
            timer.Interval = new TimeSpan(0, 0, 0, 0, 1);
            timer.Start();

        }

        private void timer_tick(object sender, object e)
        {
           if(mycontrol.Deletable)
           {
               stp.Children.Remove(mycontrol);
           }
        }

    }

--James

---

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Answer 2

我没能访问Deleteable，无论是在usercontrol内部还是外部。

你能不能把定义Deleteable的代码写成C++的？

//在MyUserControl.xaml.h中
namespace 工程名
{
	[Windows::Foundation::Metadata::WebHostHidden]
	public ref class Page7UserControl1 sealed
	{
	public:
		Page7UserControl1();
		Boolean Delerable = false;//这个属性没有被访问到
	private:
		//略
	};
}

似乎是需要进行DependencyProperty::Register，但是我不知道怎么写C++代码（错误百出）

Answer 3

你好，lxylxy，

你的方法是不行的，可以参考一下文档：Custom dependency properties。

我这里写个一个简单的例子，你看一下，是关于如何注册Dependency properities的，我这里注册了一个叫Deletable的String类，你可以改成Boolean类型如果你愿意的话：

CPP：

DependencyProperty^ MyUserControl::_LabelProperty = DependencyProperty::Register("Deletable", Platform::String::typeid, MyUserControl::typeid, nullptr);


void App99::MyUserControl::Button_Click(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
	//this->LabelProperty = "true";
	this->Deletable = "yes";
}

H：

using namespace Windows::UI::Xaml::Controls;
using namespace Windows::UI::Xaml::Interop;
using namespace Windows::UI::Xaml;
using namespace Windows::UI::Xaml::Media;
using namespace Platform;

	public ref class MyUserControl sealed
	{
	public:
		MyUserControl();
		

		static property DependencyProperty^ LabelProperty
		{
			DependencyProperty^ get() { return _LabelProperty; }
		}

		property String^ Deletable
		{
			String^ get() { return (String^)GetValue(LabelProperty); }
			void set(String^ value) { SetValue(LabelProperty, value); }
		}
	private:
		void Button_Click(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e);
		static DependencyProperty^ _LabelProperty;

	};

--James

---

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Answer 4

出现错误：（应用名是"实验"，使用UserControl的是"Page7"，UserControl的名称是"Page7Usercontrol1"）

错误	1	error LNK2001: 无法解析的外部符号 "private: static class Windows::UI::Xaml::DependencyProperty ^ 实验::Page7UserControl1::_LabelProperty" (?_LabelProperty@Page7UserControl1@实验@@0P$AAVDependencyProperty@Xaml@UI@Windows@@$AA)	实验\Page7.xaml.obj
错误	2	error LNK2001: 无法解析的外部符号 "private: static class Windows::UI::Xaml::DependencyProperty ^ 实验::Page7UserControl1::_LabelProperty" (?_LabelProperty@Page7UserControl1@实验@@0P$AAVDependencyProperty@Xaml@UI@Windows@@$AA)	实验\Page7UserControl1.xaml.obj
错误	3	error LNK2001: 无法解析的外部符号 "private: static class Windows::UI::Xaml::DependencyProperty ^ 实验::Page7UserControl1::_LabelProperty" (?_LabelProperty@Page7UserControl1@实验@@0P$AAVDependencyProperty@Xaml@UI@Windows@@$AA)	实验\XamlTypeInfo.g.obj
错误	4	error LNK1120: 1 个无法解析的外部命令	实验.exe	1

那个

static property DependencyProperty^ LabelProperty{ DependencyProperty^ get(){ return _LabelProperty; }; }

有问题，似乎是在引用_LabelProperty时的错误。

Answer 5

你好，我认为你应该自己去研究一下代码，我这里运行是完全正确的才会把代码贴给你，你或许应该检查下Class的名字或者你的代码中是否多了空格亦或者其他问题。：）

--James

---

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Answer 6

我没有遇到过这种问题，也不知道怎么解决。就是在

static property DependencyProperty^ LabelProperty
		{
			DependencyProperty^ get() { return _LabelProperty; }
		}

中如果有_LabelProperty就会报错，如果没有就不会。你能不能把项目发给我？（用onedrive或者别的网盘？）

Answer 7

好的，我上传到SkyDrive上：http://1drv.ms/1lMrfdc

我使用的是VS2013，如果你用的VS2012做项目的话，可以直接把代码粘贴复制到你项目对应的文件中即可。

编译之后应该可以看到 Deletable属性出现在控件属性列表中了。

--James

---

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Answer 8

似乎把.xaml.h文件中的命名空间声明放到#pragma once前面就好了，我再试一试

Answer 9

能不能用类似的方法定义事件？如果能，怎样触发？