c# assign 1 dimensional array to 2 dimensional array syntax

Question

I want to do something like:

object[] rowOfObjects = GetRow();//filled somewhere else
object[,] tableOfObjects = new object[10,10];

tableOfObjects[0] = rowOfObj         


        

Answer 1

So, Something like:

    public static object[] GetRow()
    {
        object[,] test = new object[10,10];
        int a = 0;
        object[] row = new object[10];
        for(a = 0; a <= 10; a++)
        {
            row[a] = test[0, a];
        }
        return row;
    }

Answer 2

If your array is an array of value types, it is possible.

int[,] twoD = new int[2, 2] {
    {0,1},
    {2,3}
};
int[] oneD = new int[2] 
    { 4, 5 };
int destRow = 1;
Buffer.BlockCopy(
    oneD, // src
    0, // srcOffset
    twoD, // dst
    destRow * twoD.GetLength(1) * sizeof(int), // dstOffset
    oneD.Length * sizeof(int)); // count
// twoD now equals
// {0,1},
// {4,5}

It is not possible with an array of objects.

Note: Since .net3.5 this will only work with an array of primitives.

Answer 3

if I have gigabyte size arrays, I would do it in C++/CLI playing with pointers and doing just memcpy instead of having gazillion slow boundary-checked array indexing operations.

Answer 4

No, if you are using a two dimensional array it's not possible. You have to copy each item.

If you use a jagged array, it works just fine:

// create array of arrays
object[][] tableOfObject = new object[10][];
// create arrays to put in the array of arrays
for (int i = 0; i < 10; i++) tableOfObject[i] = new object[10];

// get row as array
object[] rowOfObject = GetRow();
// put array in array of arrays
tableOfObjects[0] = rowOfObjects;

If you are getting all the data as rows, you of course don't need the loop that puts arrays in the array of arrays, as you would just replace them anyway.