How can i declare two dimensional array of buttons

Question

In C#, how can i declare a two dimension array of buttons?

-1: It's really not cool to remove the question you have answers for, leaving the other one left. — John H, Apr 15 '13 at 14:52
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score 7 · Answer 1 · answered Apr 15 '13 at 14:45

Yes - in the first version, the variable is not definitely assigned. In the second, it is definitely assigned, with the default value (0). So:

int a;
Console.WriteLine(a); // Error!

int a = new int();
Console.WriteLine(a); // Prints 0

I don't think I've ever actually deliberately written new int(), however. You'd usually write:

int a = 0;

as a rather more readable approach. For generic methods you could use either default(T) or new T() however, if T is constrained to be a non-nullable value type.

Arrays are a completely separate question, and should be asked separately.

score 3 · Answer 2 · answered Apr 15 '13 at 14:46

The latter (int a = new int();) assigns a value - it is basically the same as int a = 0; or int a = default(int);. This means that if it is a local variable the rules of definite assignment are happy. With the first (int a;) you can't use it until it has been assigned. For example, Console.WriteLine(a); would fail if you don't explicitly give a a value.

Note that fields (aka instance-variables and type-level variables) are inherently treated as "assigned" their default value (0 in this case), so in the case of a field it is simply redundant code.

p.s.w.g · Answer 3 · 2013-04-15T14:51:56.033

The first one just declares an integer variable without initializing it's value:

int a;

Because it hasn't been initialized, you won't be able to use this it until you've assigned it a value.

The second one declares the integer variable and initializes it to the default value.

int a = new int();

To answer the second question, you can declare a two dimensional array of any type like this:

Button[,] buttons;

To initialize the array to a certain size use

Button[,] buttons = new Button[4, 5];

Although, element item in the array will be initialized to the default value for its type.

How can i declare two dimensional array of buttons

3 Answers3