data writing from multiple controls in same file

Question

dear i have this code

StreamWriter stname = new StreamWriter("d:\\abc.text");
            string text = t11.Text;
            stname.WriteLine(text);
            stname.Close();

            StreamWriter stno = new StreamWriter("d:\\abc.text");
            string no = lpnu1.Text;
            stno.WriteLine(no);
            stno.Close();


but in output file only no is written there is no name .but if i remove  stno streamwriter then it writes name.
 how i can write both name and no in same file.both these are on button click event. i not know much c#.