The C# compiler thinks you’re trying to declare a jagged array, and doing so incorrectly. A jagged array is an array of arrays, where each array contained within the main array can have a different number of elements. A jagged array is declared as follows:
int[][] jaggedArray = new int[numElements][];
Which would create an array that could hold “numElements” arrays of integers within it.
You want to declare a multidimensional array, e.g.:
int[,] grid = new int[g.cols, g.rows];