retrieving Class object element by index

Hi,
if I have a class such as Test below and I create a new instance Test T = new Test();  How can I now reference object T by index. For instance if I want to place the value of T into a comma delimited string I could do the following

string Str = T.fld1+","+T.fld2+","+T.fld3+","+T.fld4


However I would like to be able to do something like this

for(int x=0;x<=4;x++)
{
Str=T[ x ]+","
}

Is there a way to do this ?

regards
Pat

    public class Test
    {
        public string fld1 { get; set; }
        public string fld2 { get; set; }
        public string fld3 { get; set; }
        public string fld4 { get; set; }
  public Test()
  {
fld1="test1";
fld2="test2";
fld3="test3";
fld4="test4";
  }  
}