I am considering ID is AutoIncremented field and hence inserting only Username
protected void Submit(object sender, EventArgs e)
{
string str = "a,b,c";
foreach (string s in str.Split(','))
{
string conString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
using (SqlCommand cmd = new SqlCommand("INSERT INTO UserLogin VALUES(@Username)"))
{
cmd.Parameters.AddWithValue("@Username", s);
using (SqlConnection con = new SqlConnection(conString))
{
cmd.Connection = con;
cmd.ExecuteNonQuery();
}
}
}
}