WPF - 绑定在XAML于code创建后面的物体

问题描述

可以在code（即C＃）创建的对象可用于在XAML约束力？

Can an object created in the code (ie C#) be used for binding in the XAML?

例如：

public class MyForm
{
    private MyComplexObject complexObject;

    public MyForm()
    {
        InitializeComponent();
    }

    public OnButtonClick(object sender, RoutedEventArgs e)
    {
        complexObject = new MyComplexObject();
    }
}

直到一个按钮被点击未创建

complexObject 。但是，一旦该按钮被点击我想有一个绑定到 complexObject.ID 文本框开始显示的ID。

complexObject is not created till a button is clicked. But once that button is clicked I would like to have a text box that is bound to complexObject.ID start showing the Id.

我想这样做，在XAML，如果这是可能的。

I would like to do that in the XAML if that is possible.

可以这样做？如果是这样，怎么样？

Can this be done? If so, how?

推荐答案

一种可能是让你的XAML绑定到一个属性上的code后面。该属性的吸气将返回complexObject.ID，如果complexObject！= NULL。否则，它返回的东西默认，不管是空或0或默认值（的ID类型的）。同样，对于属性的setter将指定的值应用于complexObject.ID如果complexObject是，同样，不为null。

One possibility would be to have your XAML bind to a property on your code behind. The getter for that property would return complexObject.ID, if complexObject != null. Otherwise, it returns something "default", whether that's null or 0 or default(ID's type). Similarly, the setter for that property would assign value to complexObject.ID if complexObject is, again, not null.

public int ID
{
    get
    {
        if (complexObject != null)
            return complexObject.ID;
        return 0; // or null or some appropriate default
    }
    set
    {
        if (complexObject != null)
            complexObject.ID = value;
    }
}

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