I used this code to copy one 2D array to another 2D array:
Array.Copy(teamPerformance, 0,tempPerformance,0, teamPerformance.Length);
However, when I change some data in tempPerformance then these changes also apply to teamPerformance.
What should I do to control that?
You need Clone()
double[,] arr =
{
{1, 2},
{3, 4}
};
double[,] copy = arr.Clone() as double[,];
copy[0, 0] = 2;
//it really copies the values, not a shallow copy,
//after:
//arr[0,0] will be 1
//copy[0,0] will be 2
Array.Copy() also does the exact same thing when you have a multidimensional array of value types like double as in the above example. This is rather useful when you have a jagged array (double[][] instead of double[,]) and when the inner arrays have to be cloned. The OP is most likely referring to a jagged array or a multidimensional array of reference types.This is correct: Array.Copy performs a shallow copy, so the instances of arrays inside the inner dimension get copied by reference. You can use LINQ to make a copy, like this:
var copy2d = orig2d.Select(a => a.ToArray()).ToArray();
Here is a demo on ideone.
Select() is not defined for 2D arrays.According to MS(http://msdn.microsoft.com/en-us/library/z50k9bft.aspx):
If sourceArray and destinationArray are both reference-type arrays or are both arrays of type Object, a shallow copy is performed. A shallow copy of an Array is a new Array containing references to the same elements as the original Array. The elements themselves or anything referenced by the elements are not copied. In contrast, a deep copy of an Array copies the elements and everything directly or indirectly referenced by the elements.
From what I understand reading the question, I assume the arrays are filled with reference-types, but C# does not provide a way to "just copy" a reference-type. It will only copy the reference to the object (so, then 2 things will point to the same thing).
So, putting reference-types in an array and then making a copy of the array, will not "just" make a copy of a reference-type (because C# can't do that, within an array or not).
That's why 0 of the answers given here will solve the problem. Sheng's answer is correct (but will not solve the problem) -and could maybe use a bit more explaining.
If you want to make copies of references-types, you should look into ways of doing exactly that. Like, converting them to and from JSON, or make a copy-method yourself, maybe by using Reflection.
You can also use:
int[] copy = new int[old.Length];
Buffer.BlockCopy(old, 0, copy, 0, old.Length * 4];
Note that you have to know the number of bytes you want to copy. Besides that, this method should be about best in terms of performance.
