Fastest way to create DataTable from List without for loop

Question

We have a huge list (say 100,000) which needs to be converted to DataTable for SqlBulkcopy.

Can you guide what could be the fastest way to do this without using for loop? For now we are doing it like - in below code listDos is object list

using (var dataTable = new DataTable(dataTableName))
{
    dataTable.Locale = CultureInfo.CurrentCulture;
    var columns = new[]
        {
             new DataColumn("Id", typeof(int)),
             new DataColumn("FkId", typeof(int)),
             new DataColumn("Status", typeof(string)),
             new DataColumn("RecordFrom", typeof(DateTime))
        };

    dataTable.Columns.AddRange(columns);


    foreach (ObjectDo listDo in listDos)
    {
        var row = dataTable.NewRow();

        if (rebuildDo.Id != null) row["Id"] = rebuildDo.Id;

        if (rebuildDo.FkId!= null) row["FkId"] = rebuildDo.FkId;

        row["Status"] = rebuildDo.Status;

        row["RecordFrom"] = rebuildDo.RecordFrom;

        dataTable.Rows.Add(row);
    }

    return dataTable;
}

Answer 1

The fastest way would be: not to.

SqlBulkCopy can take an IDataReader. "FastMember" (on NuGet) can expose a List<T> as an IDataReader:

List<ObjectDo> listDos = ...
using(var bcp = new SqlBulkCopy(connection)) 
using(var reader = ObjectReader.Create(listDos,
    "Id", "FkId", "Status", "RecordFrom")) 
{ 
  bcp.DestinationTableName = "SomeTable"; 
  bcp.WriteToServer(reader); 
}

This is now a direct reader over the list: no duplication of all the contents.