Calculate sum (total) of datatable columns where condition column not equal to empty using C#

No	Job Description	Total MD Used MD Balance MD	 
1	Blk-66A  	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
1.1	1st story 	3.00	3.00	0.00	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
2	Blk-66A 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
2.1	Basement  	4.00	2.00	2.00	 	 	 	 	  	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
2.2	Basement  	3.00	1.00	2.00	 
----------------------------------------------
     Total	 	 	 

<pre>No	Job Description	Total MD Used MD Balance MD	 
1	Blk-66A  	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
1.1	1st story 	3.00	3.00	0.00	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
2	Blk-66A 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
2.1	Basement  	4.00	2.00	2.00	 	 	 	 	  	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
2.2	Basement  	3.00	1.00	2.00	 
----------------------------------------------
     Total	    10.00    5.00    4.00

Decimal total = 0; ;
              leaveGrid.FooterRow.Cells[0].Text = "Total";
              leaveGrid.FooterRow.Cells[1].Font.Bold = true;
              leaveGrid.FooterRow.Cells[1].HorizontalAlign = HorizontalAlign.Left;
              for (int k = 2; k < firstTable.Columns.Count; k++)
              {

                  total = firstTable.AsEnumerable().Where(row => row.Field<String>(firstTable.Columns[k].ToString()) != "").Sum(row => row.Field<Decimal>(firstTable.Columns[k].ToString()));
                  leaveGrid.FooterRow.Cells[k].Text = total.ToString();
                  leaveGrid.FooterRow.Cells[k].Font.Bold = true;
                  leaveGrid.FooterRow.BackColor = System.Drawing.Color.Beige;
             }