在代码中获取绑定的结果 [英] Get result of a Binding in code

问题描述

我可能正在寻找错误的方式，但是：

I'm probably searching for this the wrong way, but:

有没有办法通过代码获取绑定的结果值？

is there any way to get the resulting value of a binding through code?

可能是明显的东西，但我找不到它。

Probably something glaring obvious, but I just can't find it.

推荐答案

您只需要调用绑定的 ProvideValue 方法。很难的部分是你需要传递一个有效的 IServiceProvider 到方法... 编辑：实际上，这不是真的... ProvideValue 返回一个 BindingExpression ，而不是绑定属性的值。

You just need to call the ProvideValue method of the binding. The hard part is that you need to pass a valid IServiceProvider to the method... actually, that's not true... ProvideValue returns a BindingExpression, not the value of the bound property.

您可以使用以下技巧：

class DummyDO : DependencyObject
{
    public object Value
    {
        get { return (object)GetValue(ValueProperty); }
        set { SetValue(ValueProperty, value); }
    }

    public static readonly DependencyProperty ValueProperty =
        DependencyProperty.Register("Value", typeof(object), typeof(DummyDO), new UIPropertyMetadata(null));

}

public object EvalBinding(Binding b)
{
    DummyDO d = new DummyDO();
    BindingOperations.SetBinding(d, DummyDO.ValueProperty, b);
    return d.Value;
}

...

Binding b = new Binding("Foo.Bar.Baz") { Source = dataContext };
object value = EvalBinding(b);

不是很优雅，但它的作品...

Not very elegant, but it works...

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