字段信息值转换为列表当不知道列表类型 [英] Converting FieldInfo value to a List When List type not known

问题描述

我有以下内容：

    [Serializable()]
    public struct ModuleStruct {
        public string moduleId;
        public bool isActive;
        public bool hasFrenchVersion;
        public string titleEn;
        public string titleFr;
        public string descriptionEn;
        public string descriptionFr;
        public bool isLoaded;
        public List<SectionStruct> sections;
        public List<QuestionStruct> questions;
    }

我创造了这样的一个实例，填充它（的内容无关的问题） 。我有一个函数，该函数实例化对象作为一个参数，让我们叫它模块，这个对象与其他参数的类型： module.GetType（）

这功能的话，使用反射和：

This function will then, using reflection, and:

    FieldInfo[] fields = StructType.GetFields();
    string fieldName = string.Empty;

在函数中的参数名称结构体和 StructType 。

The parameter names in the function are Struct and StructType.

通过字段名我环路结构内，拉的价值观和不同的领域，并用它做什么。一切都很好，直到我去：

I loop through the field names within Struct, pull the values and of the different fields and do something with it. All is well until I get to:

    public List<SectionStruct> sections;
    public List<QuestionStruct> questions;

该功能只知道结构体的类型通过 StructType 。在VB中，代码很简单：

The function only knows the type of Struct by StructType. In VB, the code is simply:

    Dim fieldValue = Nothing
    fieldValue = fields(8).GetValue(Struct)

和则：

    fieldValue(0)

要获得在清单部分中的第一个元素;然而，在C＃中，同样的代码不起作用，因为 fieldValue方法是一个对象，我不能做 fieldValue方法[0] 上的对象。

to get the first element in the list sections; however, in C#, the same code does not work because fieldValue is an object and I cannot do fieldValue[0] on an object.

我的问题的话，是因为该功能只能通过结构体的类型> StructType ，我怎么复制VB行为在C＃中，如果它甚至有可能？

My question, then, is given that the function only knows the type of Struct by StructType, how do I replicate the VB behaviour in C#, if it is even possible?

推荐答案

以下是这几乎是拼了一些（很简单）示例代码...我真的不想做整个事情给你，因为这可能是一个反射很大的教训：）

Here are some (very simple) example code that's pretty much spelled out... I really don't want to do the whole thing for you, because this could be a great lesson in reflection :)

private void DoSomethingWithFields<T>(T obj)
{
    // Go through all fields of the type.
    foreach (var field in typeof(T).GetFields())
    {
        var fieldValue = field.GetValue(obj);

        // You would probably need to do a null check
        // somewhere to avoid a NullReferenceException.

        // Check if this is a list/array
        if (typeof(IList).IsAssignableFrom(field.FieldType))
        {
            // By now, we know that this is assignable from IList, so we can safely cast it.
            foreach (var item in fieldValue as IList)
            {
                // Do you want to know the item type?
                var itemType = item.GetType();

                // Do what you want with the items.
            }
        }
        else
        {
            // This is not a list, do something with value
        }
    }
}

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