检查对象是字典还是列表 | 检查对象是字典还是列表

本文介绍了检查对象是字典还是列表的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

在单声道中使用.NET 2，我使用基本的使用 is 关键字和反射。

  public bool IsList（object o）
 {
 if（o == null）return false; 
 return o是IList&& 
 o.GetType（）。IsGenericType&& 
 o.GetType（）。GetGenericTypeDefinition（）。IsAssignableFrom（typeof（List>））; 
 
 $ b $ public bool IsDictionary（object o）
 {
 if（o == null）return false; 
 return o是IDictionary&& 
 o.GetType（）。IsGenericType&& 
 o.GetType（）。GetGenericTypeDefinition（）。IsAssignableFrom（typeof（Dictionary<>））; 
}

Working with .NET 2 in mono, I'm using a basic JSON library that returns nested string, object Dictionary and lists.

I'm writing a mapper to map this to a jsonData class that I already have and I need to be able to determine if the underlying type of an object is a Dictionary or a List. Below is the method I'm using to perform this test, but was wondering if theres a cleaner way?

private static bool IsDictionary(object o) {
    try {
        Dictionary<string, object> dict = (Dictionary<string, object>)o;
        return true;
    } catch {
        return false;
    }
}

private static bool IsList(object o) {
    try {
        List<object> list = (List<object>)o;
        return true;
    } catch {
        return false;
    }
}

The library I'm using is litJson but the JsonMapper class essentially doesn't work on iOS, hence the reason I am writing my own mapper.

解决方案

Use the is keyword and reflection.

public bool IsList(object o)
{
    if(o == null) return false;
    return o is IList &&
           o.GetType().IsGenericType &&
           o.GetType().GetGenericTypeDefinition().IsAssignableFrom(typeof(List<>));
}

public bool IsDictionary(object o)
{
    if(o == null) return false;
    return o is IDictionary &&
           o.GetType().IsGenericType &&
           o.GetType().GetGenericTypeDefinition().IsAssignableFrom(typeof(Dictionary<,>));
}

这篇关于检查对象是字典还是列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！