在XAML中，如何使用DependencyProperty向按钮添加命令？ [英] In XAML, how do I add a command to a button using DependencyProperty?

问题描述

我正在努力学习一些XAML语法。在第一段代码中，我将命令附加到按钮属性中的按钮：

Hi,

I'm struggling with some XAML syntax. In this first piece of code, I have attached a command to a button in the button's attributes:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"

             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"

             x:Class="MyAssembly.CodeBehindClass">

	<StackLayout>
		<Button x:Name="buttonName" Text="Press" Command="{Binding ButtonOnClickedCommand}" />
	</StackLayout>

</ContentPage>

这很好用。但是如果我想使用如下所示的替代语法呢？我可以设置文本没问题，但我无法弄清楚如何绑定命令：

This works fine. But what if I want to use the alternative syntax as shown below? I can set the text no problem, but I can't figure out how to bind the command:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"

             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"

             x:Class="MyAssembly.CodeBehindClass">

	<StackLayout>
		<Button x:Name="buttonName">
            <Button.Text>Press</Button.Text>
            <Button.Command>STRUGGLING FOR SYNTAX HERE</Button.Command>
	</StackLayout>

</ContentPage>

我想我可以更简单地表达我的问题如下：



通常，在XAML中，如果你有一个带有属性的UI元素，那么你可以用两种方式设置属性。你可以这样做：

I think I can express my question more simply as follows:

In general, in XAML, if you have a UI element with a property then you can set the property one of two ways. You can either do this:

<MyControl MyProperty="Value-which-may-be-a-binding-expression"/>

或者你可以完成同样的事情：< br $> b $ b

Or you can achieve exactly the same thing like this:

<MyControl>
    <MyControl.MyProperty>Value-goes-here</MyControl.MyProperty>
</MyControl>

我可以使用各种属性来解决这个问题，但是无法通过命令来解决这个问题。但我认为我的问题不是具体的 Command 属性;我认为这是事实，我不知道如何使用上面的第二种语法编写绑定表达式。



希望这是有道理的。







亲切的愿望~Patrick

I can get this to work with various properties but can't work out how to do it with the Command. But I think my problem is not specifically the Command property; I think it is the fact that I don't know how to write a binding expression using the second syntax above.

Hope this makes sense.



Kind wishes ~ Patrick

推荐答案

你刚才需要添加一个 Binding 元素，其元素与 {Binding ...} 标记扩展名相同：

You just need to add a Binding element, with the same properties as the {Binding ...} markup extension:

<Button x:Name="buttonName">
    <Button.Text>Press</Button.Text>
    <Button.Command>
        <Binding Path="ButtonRelaxOnClickedCommand" />
    </Button.Command>
</Button>

属性元素语法：XAML语法详细信息 [ ^ ]

在XAML中声明绑定：绑定声明概述 [ ^ ]

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