Insert datatable in to sql table

asp.net, c#

Solution

 DataTable dt = new DataTable();
 string sql = "";
 for (int i = 0; i < dt2.Rows.Count; i++)
 {
    sql = sql + "insert into InvitationData (Col1, Col2, ColN) values('"
          + dt2.Rows[i]["columnname"].ToString().Trim() + "','"
          + dt2.Rows[i]["columnname"].ToString().Trim() + "','" 
          + dt2.Rows[i]["columnname"].ToString().Trim() + "')";
 }

Problem

I have a datatable named `dt2`. And it contains some data. I want to add these data to my table named `invitationdata`. How can I write the code? Can any one help?

Original source