C# add element to list

- C# add element to list first position
- C# add element to list at index
- C# add element to list string
- C# add element to list if not exists
- C# add element to list only if not exists
- C# add element to list if not null
- C# add element to list and return
- C# add new element to list
- C# add class element to list
- C# linq add element to list
- C# reflection add element to list
- C# add element to beginning of list
- Add element to listbox c#
- Add element to list in dictionary c#
- C# add value to each element in list