How to add data to datatable

I want to add data to datatable within a loop in c# but I cannot. I use this code but it runs 1 time not more. When i=2 it dose not work. Please help.

DataTable dt = new DataTable();
dt.Columns.Add("ProductId");
dt.Columns.Add("ProductTotalPrice");
DataRow dr = dt.NewRow();

for (int i = 0; i < 10; i++)
{
    dr["ProductId"] = i.ToString();
    dr["ProductTotalPrice"] = (i*1000).ToString();
    dt.Rows.Add(dr);
}