CODEWITHSUNDEEP
c#.net
SilverDeveloper
SilverDeveloper

Reputation: 187

Items not removed from List

I have following code. In my test planList collection has 150 items. After deleting count is 75 which means that 75 items was removed from the list. Why after that countItems list is 150. It seems that items not removed from the list. Why? How I can remove items from the list.

...
planList = (IList<UserPlanned>)_jsSerializer.Deserialize(plannedValues,typeof(IList<UserPlanned>));
int count = planList.ToList().RemoveAll(eup => eup.ID <= -1);
int countItems = planList.Count;
...

Upvotes: 0

Views: 190

Answers (8)

Christian Sauer
Christian Sauer

Reputation: 10889

var templst = planList.ToList();
int count = templst.RemoveAll(eup => eup.ID <= -1);
int countItems = templst.Count;

that should work. As mentioned above, the tolist command creates a new list, from which the values are deleted. I do not know the type Of your planList, but if it is already a List, you could simply omit the .tolist

int count = planList.RemoveAll(eup => eup.ID <= -1);

excuse the shaky c#, I am writing vb.net normally

Upvotes: 1

Richard Schneider
Richard Schneider

Reputation: 35477

The planList.ToList() creates a new list that RemoveAll operates on. It does not modify the IEnumerable planList.

Try something like this:

planList = (List<UserPlanned>)_jsSerializer
     .Deserialize(plannedValues,typeof(List<UserPlanned>))
    .ToList();
int count = planList.RemoveAll(eup => eup.ID <= -1);
int countItems = planList.Count;

If you are using the JavaScriptSerializer, http://msdn.microsoft.com/en-us/library/bb355316.aspx_ Then try this:

planList = _jsSerializer.Deserialize<List<UserPlanned>>(plannedValues);

int count = planList.RemoveAll(eup => eup.ID <= -1);
int countItems = planList.Count;

Upvotes: 0

user991513
user991513

Reputation:

The code should be something like

lanList = (List<UserPlanned>)_jsSerializer.Deserialize(plannedValues,typeof(List<UserPlanned>));

int count = planList.RemoveAll(eup => eup.ID <= -1);

int countItems = planList.Count;

Upvotes: 0

Ocelot20
Ocelot20

Reputation: 10800

ToList() is creating a different list that you are removing items from. This is essentially what you're doing:

var list1 = (List<UserPlanned>)_jsSerializer.Deserialize(plannedValues,typeof(List<UserPlanned>));
var list2 = list1.ToList(); // ToList() creates a *new* list.

list2.RemoveAll(eup => eup.Id <= -1);

int count = list2.Count;
int count2 = list1.Count;

Upvotes: 1

Buh Buh
Buh Buh

Reputation: 7545

planList has not been changed.

planList.ToList()  //This creates a new list.
.RemoveAll()       //This is called on the new list.  It is not called on planList.

Upvotes: 0

Liam
Liam

Reputation: 29664

planList = (List<UserPlanned>)_jsSerializer.Deserialize(plannedValues,typeof(List<UserPlanned>));
int count = planList.RemoveAll(eup => eup.ID <= -1);
int countItems = planList.Count;

Remove the ToList(). This is creating a new list in memory so you never actually update your underlying list. You also don't need it.

Upvotes: 0

Zafer
Zafer

Reputation: 2190

Actually you are removing elements from the list that is created by ToList method, not from planList itself.

Upvotes: 3

Hamlet Hakobyan
Hamlet Hakobyan

Reputation: 33381

When you call ToList() it is copied your list, then you remove items from copy. Use:

int count = planList.RemoveAll(eup => eup.ID <= -1);

Upvotes: 6

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