ASP MVC.NET - 如何绑定 KeyValuePair? [英] ASP MVC.NET - how to bind KeyValuePair?

问题描述

可以绑定这样的属性吗?

Is it possible to bind such kind of property?

public KeyValuePair<string, string> Stuff { get; set; }

我尝试在视图中使用以下代码，但它不起作用:

I've tried to use following code in the view, but it does not work:

<%=Html.Text("Stuff", Model.Stuff.Value)%>    
<%=Html.Hidden("Model.Stuff.Key", Model.Stuff.Key)%>

推荐答案

KeyValuePair 是一个结构体，而不是一个类，所以每次调用你的Stuff 属性返回原始 KeyValuePair 的副本.因此，当您绑定到 Model.Stuff.Value 和 Model.Stuff.Key 时，您实际上是在处理 KeyValuePair 的两个不同实例;，其中没有一个来自您的模型.因此，当它们更新时，它不会更新模型中的 Stuff 属性... QED

KeyValuePair<K,V> is a structure, not a class, so each call to your Stuff property returns a copy of the original KeyValuePair. So, when you bind to Model.Stuff.Value and to Model.Stuff.Key, you are actually working on two different instances of KeyValuePair<K,V>, none of which is the one from your model. So when they are updated, it doesn't update the Stuff property in your model... QED

顺便说一下，Key 和 Value 属性是只读的，所以你不能修改它们:你必须替换 KeyValuePair 实例

By the way, the Key and Value properties are read-only, so you can't modify them : you have to replace the KeyValuePair instance

以下解决方法应该有效:

The following workaround should work :

型号:

private KeyValuePair<string, string> _stuff;
public KeyValuePair<string, string> Stuff
{
    get { return _stuff; }
    set { _stuff = value; }
}

public string StuffKey
{
    get { return _stuff.Key; }
    set { _stuff = new KeyValuePair<string, string>(value, _stuff.Value); }
}

public string StuffValue
{
    get { return _stuff.Value; }
    set { _stuff = new KeyValuePair<string, string>(_stuff.Key, value); }
}

查看:

<%=Html.Text("Stuff", Model.StuffValue)%>    
<%=Html.Hidden("Model.StuffKey", Model.StuffKey)%>

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