Multidimensional Arrays (C# Programming Guide)

Arrays can have more than one dimension. For example, the following declaration creates a two-dimensional array of four rows and two columns.

int[,] array = new int[4, 2];

The following declaration creates an array of three dimensions, 4, 2, and 3.

int[, ,] array1 = new int[4, 2, 3];

Array Initialization

You can initialize the array upon declaration, as is shown in the following example.

// Two-dimensional array. 
int[,] array2D = new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
// The same array with dimensions specified. 
int[,] array2Da = new int[4, 2] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
// A similar array with string elements. 
string[,] array2Db = new string[3, 2] { { "one", "two" }, { "three", "four" },
                                        { "five", "six" } };

// Three-dimensional array. 
int[, ,] array3D = new int[,,] { { { 1, 2, 3 }, { 4, 5, 6 } }, 
                                 { { 7, 8, 9 }, { 10, 11, 12 } } };
// The same array with dimensions specified. 
int[, ,] array3Da = new int[2, 2, 3] { { { 1, 2, 3 }, { 4, 5, 6 } }, 
                                       { { 7, 8, 9 }, { 10, 11, 12 } } };

// Accessing array elements.
System.Console.WriteLine(array2D[0, 0]);
System.Console.WriteLine(array2D[0, 1]);
System.Console.WriteLine(array2D[1, 0]);
System.Console.WriteLine(array2D[1, 1]);
System.Console.WriteLine(array2D[3, 0]);
System.Console.WriteLine(array2Db[1, 0]);
System.Console.WriteLine(array3Da[1, 0, 1]);
System.Console.WriteLine(array3D[1, 1, 2]);

// Getting the total count of elements or the length of a given dimension. 
var allLength = array3D.Length;
var total = 1;
for (int i = 0; i < array3D.Rank; i++) {
    total *= array3D.GetLength(i);
}
System.Console.WriteLine("{0} equals {1}", allLength, total);

// Output: 
// 1 
// 2 
// 3 
// 4 
// 7 
// three 
// 8 
// 12 
// 12 equals 12

You also can initialize the array without specifying the rank.

int[,] array4 = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };

If you choose to declare an array variable without initialization, you must use the new operator to assign an array to the variable. The use of new is shown in the following example.

int[,] array5;
array5 = new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };   // OK 
//array5 = {{1,2}, {3,4}, {5,6}, {7,8}};   // Error

The following example assigns a value to a particular array element.

array5[2, 1] = 25;

Similarly, the following example gets the value of a particular array element and assigns it to variable elementValue.

int elementValue = array5[2, 1];

The following code example initializes the array elements to default values (except for jagged arrays).

int[,] array6 = new int[10, 10];

See Also

Reference

Arrays (C# Programming Guide)

Single-Dimensional Arrays (C# Programming Guide)

Jagged Arrays (C# Programming Guide)

Concepts

C# Programming Guide