array of string with unknown size

Question

How is an array of string where you do not know where the array size in c#.NET?

String[] array = new String[]; // this does not work

Answer 1

Is there a specific reason why you need to use an array? If you don't know the size before hand you might want to use List<String>

List<String> list = new List<String>();

list.Add("Hello");
list.Add("world");
list.Add("!");

Console.WriteLine(list[2]);

Will give you an output of

!

MSDN - List(T) for more information

Answer 2

You can't create an array without a size. You'd need to use a list for that.

Answer 3

I think you may be looking for the StringBuilder class. If not, then the generic List class in string form:

List<string> myStringList = new List<string();
myStringList.Add("Test 1");
myStringList.Add("Test 2");

Or, if you need to be absolutely sure that the strings remain in order:

Queue<string> myStringInOriginalOrder = new Queue<string();
myStringInOriginalOrder.Enqueue("Testing...");
myStringInOriginalOrder.Enqueue("1...");
myStringInOriginalOrder.Enqueue("2...");
myStringInOriginalOrder.Enqueue("3...");

Remember, with the List class, the order of the items is an implementation detail and you are not guaranteed that they will stay in the same order you put them in.

Answer 4

I suppose that the array size if a computed value.

int size = ComputeArraySize();

// Then

String[] array = new String[size];

Answer 5

Can you use a List strings and then when you are done use strings.ToArray() to get the array of strings to work with?

Answer 6

As others have mentioned you can use a List<String> (which I agree would be a better choice). In the event that you need the String[] (to pass to an existing method that requires it for instance) you can always retrieve an array from the list (which is a copy of the List<T>'s inner array) like this:

String[] s = yourListOfString.ToArray();

Answer 7

If you will later know the length of the array you can create the initial array like this:

String[] array;

And later when you know the length you can finish initializing it like this

array = new String[42];

Answer 8

You have to specify the size of an array when you instantiate it.

You can still declare the array and instantiate it later. For instance:

string[] myArray;

...

myArray = new string[size];