Here is a function to redimension an array in csharp:-

private static void ReDim(ref TextBox[] arr, int length)
    {
        try
        {
            if (arr == null)
            {
                arr = new TextBox[length];
            }
            else
            {
                if (arr.Length != length)
                {
                    TextBox[] arrTemp = new TextBox[length];
                    if (length > arr.Length)
                    {
                        Array.Copy(arr, 0, arrTemp, 0, arr.Length);
                        arr = arrTemp;
                    }
                    else
                    {
                        Array.Copy(arr, 0, arrTemp, 0, length);
                        arr = arrTemp;
                    }
                }
            }
        }
        catch (Exception ex)
        {
            string x = ex.ToString();
            //Console.WriteLine(x);
        }
    }

This example is for a string array but you can overload it with whatever type you want.