Fastest way to convert DataTable to List using .NET 2.0

Question

I just found this post, we have almost the same scenario with the user but I only use .NET 2.0 framework and would like to know if there's a better and faster implementation with the codes below, converting datatable to list.

Thanks in advance.

namespace DataTableToListTest
{
    public partial class MainForm : Form
    {
              // Just a sample class
        class MyType
        {
            private int _foo;
            private string _bar;

            public MyType(int foo, string bar)
            {
                _foo = foo;
                _bar = bar;
            }

            public int Foo
            {
                get { return _foo; }
                set { _foo = value; }
            }

            public string Bar
            {
                get { return _bar; }
                set { _bar = value; }
            }
        }

        public MainForm()
        {
            InitializeComponent();
            dataGridView1.DataSource = GetDataSource();         
        }

        List<MyType> GetDataSource()
        {
            DataTable table = GetTable();

            for (int i = 0; i < 5000; i++)          
                table.Rows.Add(i, "Row " + i);      

            List<MyType> data = new List<MyType>(table.Rows.Count);

            foreach (DataRow row in table.Rows)     
                data.Add(new MyType((int)row[0], (string)row[1]));  
            return data;
        }


              // Suppose this method queries the database
        DataTable GetTable()
        {           
            DataTable table = new DataTable();
            table.Columns.Add("Foo", typeof(int));
            table.Columns.Add("Bar", typeof(string));

            return table;
        }
    }
}

Does your current code actually have a performance bottleneck here? — Jon Skeet, Dec 26 '11 at 15:11
Honestly, I haven't tried this in my application. Sample object that will be queried in the database using this approach is Employee data. I just used this MyType class for demo... — yonan2236, Dec 26 '11 at 15:15
@yonan2236: You should always try some code and measure it before trying to find something faster. — Jon Skeet, Dec 26 '11 at 15:16
@Jon: that's noted. LINQ actually works (looping) something like this behind the hood right? — yonan2236, Dec 26 '11 at 15:18

score 2 · Accepted Answer · answered Dec 26 '11 at 15:13

I can't think of any other optimization

int count = table.Rows.Count;
List<MyType> data = new List<MyType>(count);

for(int i = 0 ; i <count; i ++)
{
    DataRow row = tables.Rows[i];
    data.Add(new MyType((int)row[0], (string)row[1]));  
}

return data;

Fastest way to convert DataTable to List using .NET 2.0

1 Answers1