C# Return Complete SQL Query and Values?

For the purpose of troubleshooting, I would like to return the complete SQL syntax and values to a label for either desktop or web page. I tried using sqldataadapter and  commandbuilder and still only return the sql syntax and no values.

[Query]

private void InsertTable(string lastname, string midname, string firstname)
{
      string sql = " Insert Into Table1 (col1, col2, col3) values ('" + lastname + "', '" + midname + "', '" + firstname + "')";

     SqlConnection cn = new SqlConnection(cnPath);
     SqlDataAdapter da = new SqlDataAdapter(sql, cn);
     cn.Open();
     da.SelectCommand.ExecuteNonQuery();    

     label1.Text = da.InsertCommand.CommandText;

     cn.Close();
}

[Current Return]
Insert Into Table1 (col1, col2, col3) values ('lastname', 'midname', 'firstname')

[Desired Return]
Insert Into Table1 (col1, col2, col3) values (Doe, J, Jane)

Help!