Bind data to a dropdown and Append a default value

Ddl_EMP_ID.DataTextField = "EMP_FNAME";
Ddl_TEMP_ID.DataValueField = "EMP_ID";
Ddl_TEMP_ID.DataSource = dt;
Ddl_TEMP_ID.DataBind();
Ddl_TEMP_ID.Enabled = true;
Ddl_TEMP_ID.Items.Insert(0, new ListItem("Select", "-1"));