MSDN上的这个链接值得一看:如何:实现CopyToDataTable<T>，其中泛型类型T不是一个数据流

这增加了一个扩展方法，让你这样做:

// Create a sequence. 
Item[] items = new Item[] 
{ new Book{Id = 1, Price = 13.50, Genre = "Comedy", Author = "Gustavo Achong"}, 
  new Book{Id = 2, Price = 8.50, Genre = "Drama", Author = "Jessie Zeng"},
  new Movie{Id = 1, Price = 22.99, Genre = "Comedy", Director = "Marissa Barnes"},
  new Movie{Id = 1, Price = 13.40, Genre = "Action", Director = "Emmanuel Fernandez"}};

// Query for items with price greater than 9.99.
var query = from i in items
             where i.Price > 9.99
             orderby i.Price
             select i;

// Load the query results into new DataTable.
DataTable table = query.CopyToDataTable();

我认为它更方便和容易使用。

   List<Whatever> _lobj= new List<Whatever>(); 
    var json = JsonConvert.SerializeObject(_lobj);
                DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));

要将泛型列表转换为数据表，可以使用DataTableGenerator

这个库允许您将列表转换为具有多种功能的数据表，如

翻译数据表头 指定要显示的列

下面是NuGet使用FastMember的2013年更新:

IEnumerable<SomeType> data = ...
DataTable table = new DataTable();
using(var reader = ObjectReader.Create(data)) {
    table.Load(reader);
}

它使用FastMember的元编程API来获得最大的性能。如果你想将它限制到特定的成员(或强制执行顺序)，那么你也可以这样做:

IEnumerable<SomeType> data = ...
DataTable table = new DataTable();
using(var reader = ObjectReader.Create(data, "Id", "Name", "Description")) {
    table.Load(reader);
}

FastMember是Marc Gravell的一个项目。它是金色的，完全是苍蝇!

是的，这个和这个完全相反;反射就足够了——或者如果你需要更快，2.0中的HyperDescriptor，或者3.5中的Expression。实际上，HyperDescriptor应该绰绰有余。

例如:

// remove "this" if not on C# 3.0 / .NET 3.5
public static DataTable ToDataTable<T>(this IList<T> data)
{
    PropertyDescriptorCollection props =
        TypeDescriptor.GetProperties(typeof(T));
    DataTable table = new DataTable();
    for(int i = 0 ; i < props.Count ; i++)
    {
        PropertyDescriptor prop = props[i];
        table.Columns.Add(prop.Name, prop.PropertyType);
    }
    object[] values = new object[props.Count];
    foreach (T item in data)
    {
        for (int i = 0; i < values.Length; i++)
        {
            values[i] = props[i].GetValue(item);
        }
        table.Rows.Add(values);
    }
    return table;        
}

现在，只需一行代码，你就可以让它比反射快很多很多倍(通过为对象类型T启用HyperDescriptor)。

编辑重新性能查询;下面是测试结果:

Vanilla 27179
Hyper   6997

我怀疑瓶颈已经从成员访问转移到数据表性能…我怀疑你在这方面还能提高多少……

代码:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
public class MyData
{
    public int A { get; set; }
    public string B { get; set; }
    public DateTime C { get; set; }
    public decimal D { get; set; }
    public string E { get; set; }
    public int F { get; set; }
}

static class Program
{
    static void RunTest(List<MyData> data, string caption)
    {
        GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
        GC.WaitForPendingFinalizers();
        GC.WaitForFullGCComplete();
        Stopwatch watch = Stopwatch.StartNew();
        for (int i = 0; i < 500; i++)
        {
            data.ToDataTable();
        }
        watch.Stop();
        Console.WriteLine(caption + "\t" + watch.ElapsedMilliseconds);
    }
    static void Main()
    {
        List<MyData> foos = new List<MyData>();
        for (int i = 0 ; i < 5000 ; i++ ){
            foos.Add(new MyData
            { // just gibberish...
                A = i,
                B = i.ToString(),
                C = DateTime.Now.AddSeconds(i),
                D = i,
                E = "hello",
                F = i * 2
            });
        }
        RunTest(foos, "Vanilla");
        Hyper.ComponentModel.HyperTypeDescriptionProvider.Add(
            typeof(MyData));
        RunTest(foos, "Hyper");
        Console.ReadLine(); // return to exit        
    }
}

将通用列表转换为数据表

使用Newtonsoft.Json;

public DataTable GenericToDataTable(IList<T> list)
{
    var json = JsonConvert.SerializeObject(list);
    DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));
    return dt;
}

 Dim counties As New List(Of County)
 Dim dtCounties As DataTable
 dtCounties = _combinedRefRepository.Get_Counties()
 If dtCounties.Rows.Count <> 0 Then
    For Each row As DataRow In dtCounties.Rows
      Dim county As New County
      county.CountyId = row.Item(0).ToString()
      county.CountyName = row.Item(1).ToString().ToUpper()
      counties.Add(county)
    Next
    dtCounties.Dispose()
 End If