查看物业 - 两次绑定 [英] View property - bind twice

问题描述

是否有可能控制的相同属性绑定不止一次？

要例如：

 ＆LT;弹出ISOPEN ={绑定路径=（本地：ListViewBehavior.IsColumnHeaderClicked）
    的RelativeSource = {的RelativeSource FindAncestor，AncestorType = GridViewColumnHeader}}...
 

正如你所看到 Popup.IsOpen 势必附加属性。我想将其绑定到视图模型 IsPopupOpened ，但不知道怎么样。

---

试图@Arhiman答案没有成功：

 ＆LT; Popup.IsOpen＆GT;
    ＆LT; MultiBinding转换器={本地：MultiBindingConverter}＆GT;
        ＆LT;绑定路径=（本地：ListViewBehavior.IsColumnHeaderClicked）
                 的RelativeSource ={的RelativeSource FindAncestor，AncestorType = GridViewColumnHeader}/＆GT;
        ＆LT;绑定路径=DataContext.IsPopupId
                 的RelativeSource ={的RelativeSource FindAncestor，AncestorType =用户控件}/＆GT;
    ＆LT; / MultiBinding＆GT;
＆LT; /Popup.IsOpen>
 

的天真的转换器逻辑：

 公共类MultiBindingConverter：的MarkupExtension，IMultiValueConverter
{
    公共MultiBindingConverter（）{}    公众覆盖对象ProvideValue（的IServiceProvider的ServiceProvider）=＆GT;这个;    [对象] _old;    公共对象转换（对象[]值类型TARGETTYPE，对象参数，CultureInfo的文化）
    {
        如果（_old == NULL）
            _old = values​​.ToArray（）;
        //检查是否值之一被改变 - 这种改变是一种新的价值
        的for（int i = 0; I＆LT; values​​.Length;我++）
            如果（值[I]！= _old [I]）
            {
                _old = values​​.ToArray（）;
                返回值[I];
            }
        返回值[0];
    }    //复制当前值
    公用对象[] ConvertBack（对象的值，类型[] targetTypes，对象参数，CultureInfo的文化）=＆GT;
        Enumerable.Repeat（值，targetTypes.Length）.ToArray（）;
}
 

解决方案

您可以简单地使用一个MultiBinding有一个转换器来实现你想要的逻辑。

 ＆LT; Popup.IsOpen＆GT;
    ＆LT; MultiBinding转换器={StaticResource的openLogicConverter}＆GT;
        ＆LT;绑定路径=MyAttachedProperty... /＆GT;
        ＆LT;绑定路径=IsPopupOpened/＆GT;
    ＆LT; / MultiBinding＆GT;
＆LT; /Popup.IsOpen>
 

我通常把这个逻辑视图模型，但它是一个AttachedProperty，有事直接在浏览似乎更适合我。

Is it possible to bind the same property of the control more than once?

To example:

<Popup IsOpen="{Binding Path=(local:ListViewBehavior.IsColumnHeaderClicked),
    RelativeSource={RelativeSource FindAncestor,  AncestorType=GridViewColumnHeader}}" ...

As you can see Popup.IsOpen is bound to attached property. I'd like to bind it to ViewModel IsPopupOpened, but have no idea how.

---

Trying @Arhiman answer without much success:

<Popup.IsOpen>
    <MultiBinding Converter="{local:MultiBindingConverter}">
        <Binding Path="(local:ListViewBehavior.IsColumnHeaderClicked)"
                 RelativeSource="{RelativeSource FindAncestor, AncestorType=GridViewColumnHeader}" />
        <Binding Path="DataContext.IsPopupId"
                 RelativeSource="{RelativeSource FindAncestor, AncestorType=UserControl}" />
    </MultiBinding>
</Popup.IsOpen>

Naive converter logic:

public class MultiBindingConverter : MarkupExtension, IMultiValueConverter
{
    public MultiBindingConverter() { }

    public override object ProvideValue(IServiceProvider serviceProvider) => this;

    object[] _old;

    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        if (_old == null)
            _old = values.ToArray();
        // check if one of values is changed - that change is a new value
        for (int i = 0; i < values.Length; i++)
            if (values[i] != _old[i])
            {
                _old = values.ToArray();
                return values[i];
            }
        return values[0];
    }

    // replicate current value
    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture) =>
        Enumerable.Repeat(value, targetTypes.Length).ToArray();
}

解决方案

You could simply use a MultiBinding with a converter to implement the logic you'd like.

<Popup.IsOpen>
    <MultiBinding Converter="{StaticResource openLogicConverter}">
        <Binding Path="MyAttachedProperty" ... />
        <Binding Path="IsPopupOpened" />
    </MultiBinding>
</Popup.IsOpen>

I'd usually put this logic in the ViewModel, but as it is an AttachedProperty, something directly in the View seems more appropriate to me.

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