实例化后的SelectList设置选定值 [英] Set selected value in SelectList after instantiation

问题描述

我说得对认为有没有办法在创建后设置在C＃类的SelectList所选择的价值？ 是不是有点傻？

Am I right to think that there is no way to set the selected value in the C# class SelectList after it is created? Isn't that a bit silly?

推荐答案

我觉得你是战斗的框架。数据进入你的意见，应在最后一分钟（LPM）创建。

I think you are fighting the framework. The data going into your views should be created at the Last Possible Minute (LPM).

这样的想法，一个的SelectList 是一种喂的DropDownList HTML帮手。这是不是在你决定如何处理它来存储数据的地方。

Thinking this way, a SelectList is a type to feed the DropDownList HTML helper. It is NOT a place to store data while you decide how to process it.

有一个更好的解决办法是检索数据成名单，其中，T＆GT; 然后初始化的SelectList （ S），当您需要。这种做法的一个直接的好处是，它可以让你重用你的名单，其中，T＆GT; 的多个的DropDownList ，如：

A better solution would be to retrieve your data into a List<T> and then initialize the SelectList(s) when you need to. An immediate benefit of this practice is that it allows you to reuse your List<T> for more than one DropDownList, such as:

Country of birth
Country of residence

这些 SelectLists 全部使用类型的国家名单名单，其中，国家＆GT;

These SelectLists all use the Countries list of type List<Country>.

您可以使用名单，其中，T＆GT; 在最后一分钟就像这个例子：

You can use your List<T> at the 'last minute' like in this example:

public class TaxCheatsFormViewModel
{
    private List<Country> countries { get; set; }

    public TaxCheat Cheat { get; private set; }
    public SelectList CountryOfBirth { get; private set; }
    public SelectList CountryOfResidence { get; private set; }
    public SelectList CountryOfDomicile { get; private set; }

    public TaxCheatsFormViewModel(TaxCheat baddie)
    {
        TaxCheat = baddie;
        countries = TaxCheatRepository.GetList<Country>();
        CountryOfBirth = new SelectList(countries, baddie.COB);
        CountryOfResidence = new SelectList(countries, baddie.COR);
        CountryOfDomicile = new SelectList(countries, baddie.COD);
    }
}

关键是，你应该让你的数据在名单，其中，T＆GT; ，直到你真正需要它输出;最后一分钟（LPM）。

The point being that you should keep your data in a List<T> till you really need to output it; the last possible minute (LPM).

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