c# - Loop through a dictionary collection to search a key and increase value -

i have dictionary put in session , on each button click need perform operation.

itemcoll = new dictionary<int, int>(); 

i want search key maintain in session variable, if key exist want increase value 1 corresponding key, how can achive this.

i trying follows:

if (session["currcatid"] != null) {     currcatid = (int)(session["currcatid"]);     // first time, next time fetch session     // , want search currcatid , increase value     // corresponding key 1.     itemcoll = new dictionary<int, int>();     itemcoll.add(currcatid, 1);     session["itemcoll"] = itemcoll;                             } 

you're pretty close, need manage few more cases:

if (session["currcatid"] != null) {     currcatid = (int)(session["currcatid"]);      // if dictionary isn't in session yet add     if (session["itemcoll"] == null)     {         session["itemcoll"] = new dictionary<int, int>();     }      // can safely pull out every time     itemcoll = (dictionary<int, int>)session["itemcoll"];      // if currcatid doesn't have key yet, let's add     // initial value of 0     if (!itemcoll.containskey(currcatid))     {         itemcoll.add(currcatid, 0);     }      // can safely increment     itemcoll[currcatid]++; }