可以使用XAML来设置控件的嵌套属性（属性的属性）吗？ [英] Can I use XAML to set a nested property (property of the value of a property) of a control?

问题描述

我有一个WPF控件，它暴露了一个孩子（从它的ControlTemplate）通过只读属性。目前它只是一个CLR属性，但我不认为这有什么区别。

我想要能够设置子控件上的一个属性从我实例化主控制的XAML。 （实际上，我想约束它，但我认为设置它将是一个很好的第一步。）

这里有一些代码：

  public class ChartControl：Control 
 {
 public IAxis XAxis {get;私人集合
 
 public override void OnApplyTemplate（）
 {
 base.OnApplyTemplate（）; 
 
 this.XAxis = GetTemplateChild（PART_XAxis）作为IAxis; 
} 
} 
 
 public interface IAxis 
 {
 //这是我要设置的属性
 double最大{get;组; } 
 $ b public class Axis：FrameworkElement，IAxis 
 {
 public static readonly DependencyProperty MaximumProperty = DependencyProperty.Register（Maximum，typeof（double），typeof （Axis），新的FrameworkPropertyMetadata（20.0，FrameworkPropertyMetadataOptions.AffectsRender，OnAxisPropertyChanged））; 
 
 public double最大
 {
 get {return（double）GetValue（MaximumProperty）; } 
 set {SetValue（MaximumProperty，value）; } 
} 
} 
  

这里有两种方法可以设置XAML中的嵌套属性（无法编译）：

 <！ -  
这不起作用：
属性XAxis.Maximum不存在于XML命名空间http://schemas.microsoft.com/winfx/2006/xaml/presentation中。 
在XAxis类型中找不到attachable属性Maximum。 
  - > 
< local：ChartControl XAxis.Maximum ={Binding Maximum}/> 
 
<！ -  
这不起作用：
无法在属性元素上设置属性。 
  - > 
< local：ChartControl> 
< local：ChartControl.XAxis Maximum ={Binding Maximum}/> 
< / local：ChartControl> 
  

这是否可以？

没有我想我只需要在受控于孩子（在模板中）的主要控件上公开DP。不是那么糟糕，我猜，但我只是试图避免在主要控制下的财产爆炸。

干杯。

解决方案

您不能这样做...您可以通过其绑定中的路径访问嵌套属性，但不能在定义属性的值时。 / p>

你必须这样做：

 < local： ChartControl> 
< local：ChartControl.XAxis> 
< local：Axis Maximum ={Binding Maximum}/> 
< / local：ChartControl.XAxis> 
< / local：ChartControl> 
  

I've got a WPF Control that exposes one of it's children (from it's ControlTemplate) through a read-only property. At the moment it's just a CLR property, but I don't think that makes any difference.

I want to be able to set one of the properties on the child control from the XAML where I'm instantiating the main control. (Actually, I would like to bind to it, but I think setting it would be a good first step.)

Here's some code:

public class ChartControl : Control
{
    public IAxis XAxis { get; private set; }

    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        this.XAxis = GetTemplateChild("PART_XAxis") as IAxis;
    }
}

public interface IAxis
{
    // This is the property I want to set
    double Maximum { get; set; }
}

public class Axis : FrameworkElement, IAxis
{
    public static readonly DependencyProperty MaximumProperty = DependencyProperty.Register("Maximum", typeof(double), typeof(Axis), new FrameworkPropertyMetadata(20.0, FrameworkPropertyMetadataOptions.AffectsRender, OnAxisPropertyChanged));

    public double Maximum
    {
        get { return (double)GetValue(MaximumProperty); }
        set { SetValue(MaximumProperty, value); }
    }
}

Here's the two ways I can think of setting the nested property in XAML (neither compile):

<!-- 
    This doesn't work:
    "The property 'XAxis.Maximum' does not exist in XML namespace 'http://schemas.microsoft.com/winfx/2006/xaml/presentation'."
    "The attachable property 'Maximum' was not found in type 'XAxis'."
-->
<local:ChartControl XAxis.Maximum="{Binding Maximum}"/>

<!-- 
    This doesn't work: 
    "Cannot set properties on property elements."
-->
<local:ChartControl>
    <local:ChartControl.XAxis Maximum="{Binding Maximum}"/>
</local:ChartControl>

Is this even possible?

Without it I guess I'll just need to expose DP's on the main control that get bound through to the children (in the template). Not so bad, I guess, but I was just trying to avoid an explosion of properties on the main control.

Cheers.

解决方案

You can't do it like this... you can access nested properties through its path in a binding, but not when you define the value of the property.

You have to do something like that :

<local:ChartControl>
    <local:ChartControl.XAxis>
        <local:Axis Maximum="{Binding Maximum}"/>
    </local:ChartControl.XAxis>
</local:ChartControl>

这篇关于可以使用XAML来设置控件的嵌套属性（属性的属性）吗？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！