Aspose CheckCell vs Aspose WorkSheet.Cell[r,c] - excel

Question

My excel has millions of records (approx 1.1M) and when I am trying to read cell by cell using WorkSheet.Cells[row,cloumn] it is very slow.
Rather if I use, WorkSheet.Cells.CheckCell(row, column) performance is very good.
Can you please let me know the difference between these two API's

Answer 1

Worksheet.Cells.CheckCell() is the most right way to check if the cell exists or not.
CheckCell method will not instantiate the cell if it does not exist. On the other hand, Cells[r, c] will instantiate the cell if it does not exist.
It means,
CheckCell can return null or cell object.
But Cells[r, c] will never return null and will always return cell object.
Since Cells[r, c] will always return cell object and if it does not already exist, it will create it, this is why, it affects the performance. If you want to iterate all the existing cells in your worksheet without creating new cells, please use Worksheet.Cells.GetEnumerator() method.
Please see the following sample code, its comments and console output for a reference.
C#
//Create a workbook
Workbook wb = new Workbook();
//Access first worksheet
Worksheet ws = wb.Worksheets[0];
//At the moment, Cell B4 does not exist
//Therefore check cell will return null
Cell cell = ws.Cells.CheckCell(3, 1);
Console.WriteLine(cell == null); //<<<<<<<<<< It will print - True
//After this statement, cell B4 will be instantiated and it will exist
var o = ws.Cells[3, 1];
//Now check cell will not return null, but it will return cell B4
cell = ws.Cells.CheckCell(3, 1);
Console.WriteLine(cell == null);//<<<<<<<<<< It will print - False
Console Output
True
False
Update - 1
Please see the following sample code, its comments and console output. It illustrates that GetEnumerator() method returns non-empty and empty cells as well.
C#
//Create a workbook
Workbook wb = new Workbook();
//Access first worksheet
Worksheet ws = wb.Worksheets[0];
//Create empty cells
//Cell A4, B6, C8 and D10 all are empty
var o = ws.Cells["A4"];
o = ws.Cells["B6"];
o = ws.Cells["C8"];
o = ws.Cells["D10"];
//Get cells enumerator
var i = ws.Cells.GetEnumerator();
//Iterate all cells
while(i.MoveNext())
{
Cell cell = i.Current as Cell;
//Print cell name
Debug.WriteLine(cell.Name);
}
Console Output
A4
B6
C8
D10
Note: I am working as Developer Evangelist at Aspose