system.invalidoperationexception collection was modified enumeration operation may not execute at System.Collections.Generic.Dictionary

Question

I am getting this error in this line

Error Says:

system.invalidoperationexception collection was modified enumeration operation may not execute at System.Collections.Generic.Dictionary '2.ValueCollection.Enumerator.MoveNext<>

Line which I have error in

foreach (ISkill skill in client.Spells.Values)

When I tried to replace foreach with for I got three errors

UPDATE: My full code

 public static void SaveSpells(GameState client)
    {
        if (client.Fake) return;
        if (client.TransferedPlayer) return;
        if (((client.Entity != null) && (client.Spells != null)) && (client.Spells.Count != 0))
        {


            foreach (ISkill skill in client.Spells.Values)
            {
                DeadPool.Database.MySqlCommand command;
                if (skill.Available)
                {
                  //  if (skill.PreviousLevel != skill.Level)
                    {
                        command = new DeadPool.Database.MySqlCommand(MySqlCommandType.UPDATE);
                        command.Update("skills").Set("LevelHu2", skill.LevelHu2).Set("LevelHu", (long)skill.Souls).Set("Level", (long)skill.Level).Set("PreviousLevel", (long)skill.Level).Set("PreviousLevel", (long)skill.PreviousLevel).Set("Experience", (long)skill.Experience).Where("EntityID", (long)client.Entity.UID).And("ID", (long)skill.ID).Execute();
                    }
                }
                else
                {
                    skill.Available = true;
                    command = new DeadPool.Database.MySqlCommand(MySqlCommandType.INSERT);
                    command.Insert("skills").Set("LevelHu2", skill.LevelHu2).Set("LevelHu2", skill.LevelHu2).Insert("LevelHu", (long)skill.Souls).Insert("Level", (long)skill.Level).Insert("PreviousLevel", (long)skill.Level).Insert("Experience", (long)skill.Experience).Insert("EntityID", (long)client.Entity.UID).Insert("ID", (long)skill.ID).Execute();
                }
            }
        }
    }

Don't add to or remove from `client.Spells` while iterating. This also includes from different threads. And, remember to search first.. — user2864740, Aug 23 '16 at 04:01

score 1 · Answer 1 · answered Aug 23 '16 at 04:10

1

I suspect inside the loop you are modifying the collection, which is causing an exception.

foreach doesn't allow mutations on what you iterate, use for instead.

answered Aug 23 '16 at 04:10

Hari Prasad

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When i use 'For' instead of 'foreach' i'm getting error 'Only assignment, call, increment, decrement, and new object expressions can be used as a statement' and also 2 others error which is '; expected' @Hari Prasad – Kareem Nabil Aug 23 '16 at 04:18
Can you update with the updated code(after changing it to for loop)? and highlight where you are getting error? – Hari Prasad Aug 23 '16 at 05:28

system.invalidoperationexception collection was modified enumeration operation may not execute at System.Collections.Generic.Dictionary

1 Answers1