Windows窗体上的数据绑定在对象图上可能具有null属性？ [英] Databinding in windows forms on an object graph with possible null properties?

问题描述

如果我有这样的对象图：

If I have an object graph like this:

class Company {
  public Address MainAddress {...}
}

class Address {
  public string City { ... }
}

Company c = new Company();
c.MainAddress = new Address();
c.MainAddress.City = "Stockholm";

并将数据绑定到使用以下控件的控件：

and databind to a control using:

textBox1.DataBinding.Add( "Text", c, "MainAddress.City" );

一切都很好，但是如果我绑定到：

Everything is fine, but If I bind to:

Company c2 = new Company();

c2 自崩溃以来使用的相同语法 MainAddress 属性为空。我想知道是否有一个自定义的Binding类，可以在此处为所有可能的路径设置侦听器，并在/如果我稍后在应用程序中设置 MainAddress 属性。

c2 using the same syntax it crashes since the MainAddress property is null. I wonder if there is a custom Binding class that can set up listeners for all the possible paths here and bind to the actual object dynamically when/if I sometime later in the application set the MainAddress property.

推荐答案

您应更改属性MainAddress的吸气剂以执行此空检查，并返回空MainAddress

You should change the getter of the property MainAddress to do this null check, and return an "empty MainAddress"

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