Question

I have this code:

List<string> list = new List<string>(30);

list.Insert(1, "string 1");
list.Insert(10, "string 10");
list.Insert(5, "string 5");

The run-time is crashing on sting 10 with exception Index must be within the bounds of the List

What I can’t understand is that I have defined a list with 30 items, so why does this crash and what is the point of defining the 30 if I can’t add an items in such way?

Answer 1

The list is still empty when initialized. The parameter ’30’ means it will simply have the capacity of 30 items.

If you insist on using a list instead of an array, you must first add 30 items and then you can set them with their appropriate index.

The easiest way to do this would be:

List<string> list = new string[30].ToList();

list[1] = "string 1";
list[10] = "string 10";
list[5] = "string 5";

Also note that when you’re using Insert, it will basically Add the item to a certain index, so the number of items in the list will grow.