LINQ - 从对象数组中选择属性到强运行时类型数组？

Question

尝试通过数组绑定（Oracle）改进插入方法，该方法需要将强类型与 Array.

第一步，我需要List<object>到每个属性Array。 但是，当我使用 LINQ 到Select 属性然后ToArray() 时，我得到了object[]。

//Reflection
foreach(var prop in typeof(Person).GetProperties())
    personList.Select(x => prop.GetValue(x)).ToArray();

看起来不能使用泛型ToArray<T>() 来处理运行时属性类型。

代码 https://dotnetfiddle.net/7ogYNJ

using System;
using System.Collections.Generic;
using System.Linq;              
using System.Reflection;
using System.Diagnostics;

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public class Program
{
    public static void Main()
    {

        List<Person> personList = new List<Person>();
        personList.Add(new Person(){Name = "aaa", Age = 10});
        personList.Add(new Person(){Name = "bbb", Age = 5});
        for(int i = 0; i< 10; i++)
        {
            personList.AddRange(personList);
        }


        Dictionary<string, PropertyInfo> propDict = typeof(Person).GetProperties(BindingFlags.Public | BindingFlags.Instance)
            .Where(p => p.CanRead && !p.GetIndexParameters().Any()).AsEnumerable().ToDictionary(x => x.Name, x => x);
        int count = personList.Count;

        Stopwatch sw = new Stopwatch();
        //1. get Object[]
        sw.Restart();
        foreach(var prop in propDict)
        {
            var tempArray = personList.Select(x => prop.Value.GetValue(x)).ToArray();
            Console.WriteLine(tempArray.GetType().Name);//Object[]
        }
        sw.Stop();
        Console.WriteLine("Spend" + sw.ElapsedMilliseconds + "us");

        //2. not work, return Object[]
        sw.Restart();
        foreach(var prop in propDict)
        {
            var tempArray = personList.Select(x => Convert.ChangeType(prop.Value.GetValue(x), prop.Value.PropertyType)).ToArray();
            Console.WriteLine(tempArray.GetType().Name);//Object[]
        }
        sw.Stop();
        Console.WriteLine("Spend" + sw.ElapsedMilliseconds + "us");

        //3. work, via ArrayCopy, try to find other method
        sw.Restart();
        foreach(var prop in propDict)
        {
            var tempArray = personList.Select(x => prop.Value.GetValue(x)).ToArray();
            Array stronglyTypeArray = Array.CreateInstance(prop.Value.PropertyType, count);
            Array.Copy(tempArray, stronglyTypeArray, count);
            Console.WriteLine(stronglyTypeArray.GetType().Name);//String[]//Int32[]
        }
        sw.Stop();
        Console.WriteLine("Spend" + sw.ElapsedMilliseconds + "us");

        //4. work, if-condition slower than method 3
        sw.Restart();
        foreach(var prop in propDict)
        {
            dynamic tempArray;
            if(prop.Value.PropertyType == typeof(System.String))
            {
                tempArray = personList.Select(x =>  prop.Value.GetValue(x).ToString()).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Boolean))
            {
                tempArray = personList.Select(x =>  (bool)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Byte))
            {
                tempArray = personList.Select(x =>  (byte)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Char))
            {
                tempArray = personList.Select(x =>  (char)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Decimal))
            {
                tempArray = personList.Select(x =>  (decimal)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Double))
            {
                tempArray = personList.Select(x =>  (double)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Int16))
            {
                tempArray = personList.Select(x =>  (short)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Int32))
            {
                tempArray = personList.Select(x =>  (int)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Int64))
            {
                tempArray = personList.Select(x =>  (long)prop.Value.GetValue(x)).ToArray();
            }
            else if(prop.Value.PropertyType == typeof(System.Single))
            {
                tempArray = personList.Select(x =>  (float)prop.Value.GetValue(x)).ToArray();
            }
            else
            {
                tempArray = personList.Select(x =>  prop.Value.GetValue(x)).ToArray();
            }
            Console.WriteLine(tempArray.GetType().Name);//Object[]
        }
        sw.Stop();
        Console.WriteLine("Spend" + sw.ElapsedMilliseconds + "us");
    }
}

在方法2中，我尝试使用Convert.Change，但它不起作用。
在方法 3 中，通过Array.CreateInstance 和ArrayCopy，它可以工作。
方法四中，使用if-condition进行强制转换，但比方法三慢，无法处理非预期类型。

我的候选人是方法 3。 有没有更有效的方法来使用 Array 获取强类型？

顺便说一句，有一个delegate方法可以更快地获取属性值https://stackoverflow.com/a/17440469/12620047

Answer 1

如何打开类型（通常不赞成）并使用Cast<>() 创建正确的Array：

foreach (var prop in propDict) {
    var qryProp = personList.Select(x => prop.Value.GetValue(x));
    Array tempArray = null;
    switch (Type.GetTypeCode(prop.Value.PropertyType)) {
        case TypeCode.String:
            tempArray = qryProp.Cast<string>().ToArray();
        break;
        case TypeCode.Int32:
            tempArray = qryProp.Cast<Int32>().ToArray();
        break;
    }
    Console.WriteLine(tempArray.GetType().Name);//String[]/Int32[]
}