Question

I am not quite sure what exactly goes on when I run the code below to add four values (a, b, c ,d ) into my hash table with C#. But I do know that I get wrong answer. after the loop finished, I get 4 ds stored in my hash table . Help me, Please!

Hashtable cirlTmp = new Hashtable();

CycleLink mycylink = new CycleLink();
int i = 0;
for (i = 0; i < 4; i++)
{
      mycylink.link_id = i;
      mycylink.begine_state = i;//
      mycylink.end_state = 1 + i;
      mycylink.proscDescrp = (process_descrp)i;
      lock (cirlTmp.SyncRoot)
      {
           cirlTmp.Add(i, mycylink);
      }   
 }

what I get in the cirlTemp is

  [3]: link_id=3 begine_state=3 end_state=4 proscDesrp=4;
  [2]: link_id=3 begine_state=3 end_state=4 proscDesrp=4;
  [1]: link_id=3 begine_state=3 end_state=4 proscDesrp=4;
  [0]: link_id=3 begine_state=3 end_state=4 proscDesrp=4;

……. Any hint will be helpful! thanks

Answer 1

move your CycleLink declaration inside the for loop, you just have a reference to the same object in 4 places in your Hashtable instead of 4 different object

and the value of your object is just the value you set it to in the last run in your loop, that’s when i was 3

Hashtable cirlTmp = new Hashtable();

int i = 0;
for (i = 0; i < 4; i++)
{
  CycleLink mycylink = new CycleLink();
  mycylink.link_id = i;
  mycylink.begine_state = i;//
  mycylink.end_state = 1 + i;
  mycylink.proscDescrp = (process_descrp)i;
  lock (cirlTmp.SyncRoot)
  {
    cirlTmp.Add(i, mycylink);
  }   
}