how to edit or modify a list collection which is iterating

Question

i am having two list collections one for new persons and one for existing persons and my condition is if the record in new person matches with existing person it should remove the record from existing person for that i am using the following code foreach(var p in existingperson) { if(newperson.id==p.id) { existingperson.remove(p); return true; } else { return false; } } its throwing an exception that i cant change collection in iteration.for using for loop i dont know the count of existing records..please help

Sudheer Kumar · Answer

not working catcher wrong getting an error as cannot convert from string to myperson

Catcher Wong · Answer

static void Main(string[] args) { var personList = new List (); personList.Add( new Person { Id = 1 }); personList.Add( new Person { Id = 2 }); personList.Add( new Person { Id = 3 }); personList.Add( new Person { Id = 4 }); personList.Add( new Person { Id = 5 }); var newPerson = new Person() { Id= 4 }; var tmp = personList; Test(newPerson personList tmp); Console.WriteLine(personList.Count); Console.ReadKey(); } static bool Test(Person newPerson List existingpersonList tmp) { bool flag = false ; for ( int i = 0; i { if (newPerson.Id == tmp[i].Id) { existingperson.Remove(tmp[i]); flag = true ; } } return flag; } you can try this!