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    <p>Here's a nice 2013 update using <a href="http://nuget.org/packages/FastMember/" rel="noreferrer">FastMember</a> from NuGet:</p> <pre><code>IEnumerable&lt;SomeType&gt; data = ... DataTable table = new DataTable(); using(var reader = ObjectReader.Create(data)) { table.Load(reader); } </code></pre> <p>This uses the FastMember's meta-programming API for maximum performance. If you want to restrict it to particular members (or enforce the order), then you can do that too:</p> <pre><code>IEnumerable&lt;SomeType&gt; data = ... DataTable table = new DataTable(); using(var reader = ObjectReader.Create(data, "Id", "Name", "Description")) { table.Load(reader); } </code></pre> <p>Editor's <em>Dis</em>/<strong>claimer:</strong> FastMember is a Marc Gravell project. Its gold and full-on flys!</p> <hr> <p>Yes, this is pretty much the exact opposite of <a href="https://stackoverflow.com/questions/545328/asp-net-potential-memory-leaks-converting-datatable-to-lists/545429#545429">this</a> one; reflection would suffice - or if you need quicker, <a href="http://www.codeproject.com/KB/cs/HyperPropertyDescriptor.aspx" rel="noreferrer"><code>HyperDescriptor</code></a> in 2.0, or maybe <code>Expression</code> in 3.5. Actually, <code>HyperDescriptor</code> should be more than adequate.</p> <p>For example:</p> <pre><code>// remove "this" if not on C# 3.0 / .NET 3.5 public static DataTable ToDataTable&lt;T&gt;(this IList&lt;T&gt; data) { PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T)); DataTable table = new DataTable(); for(int i = 0 ; i &lt; 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 &lt; values.Length; i++) { values[i] = props[i].GetValue(item); } table.Rows.Add(values); } return table; } </code></pre> <p>Now with one line you can make this many many times faster than reflection (by enabling <a href="http://www.codeproject.com/KB/cs/HyperPropertyDescriptor.aspx" rel="noreferrer"><code>HyperDescriptor</code></a> for the object-type <code>T</code>).</p> <hr> <p>edit re performance query; here's a test rig with results:</p> <pre><code>Vanilla 27179 Hyper 6997 </code></pre> <p>I suspect that the bottleneck has shifted from member-access to <code>DataTable</code> performance... I doubt you'll improve much on that...</p> <p>code:</p> <pre><code>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&lt;MyData&gt; data, string caption) { GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced); GC.WaitForPendingFinalizers(); GC.WaitForFullGCComplete(); Stopwatch watch = Stopwatch.StartNew(); for (int i = 0; i &lt; 500; i++) { data.ToDataTable(); } watch.Stop(); Console.WriteLine(caption + "\t" + watch.ElapsedMilliseconds); } static void Main() { List&lt;MyData&gt; foos = new List&lt;MyData&gt;(); for (int i = 0 ; i &lt; 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 } } </code></pre>
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    1. POConvert generic List/Enumerable to DataTable?
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    1. COnice one, but isn't this kinda slow? just wondering.
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    2. COWell "as is", it'll be about as quick as reflection. If you enable HyperDescriptor, it will thrash reflection hands down... I'll run a quick test... (2 minutes)
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    3. COExpression was mentioned for 3.5. If used how would it affect the code, is there any sample ?
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