Question

I am trying to add 2 decimal values and save it to a new datacolumn. But i realize its not how i should do it. Where am i thinking wrong, Please let me know. Thank you! This is in Visual Studio 2005 using c#..

 Dataset ds = new DataSet();
 DataColumn newColumn2;
 newColumn2 = new DataColumn("TotalAmount");
 decimal TotalAmountSold = 0;
 for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
 {
     TotalAmountSold = Convert.ToDecimal(ds.Tables[0].Rows[i]["AmountSold"]) + Convert.ToDecimal(ds.Tables[0].Rows[i]["AmountUpgraded"]);
 }
 TotalAmountSold = Math.Round(Convert.ToDecimal(TotalAmountSold.ToString()), 2);
 newColumn2.Expression = TotalAmountSold.ToString();
 ds.Tables[0].Columns.Add(newColumn2);

Answer 1

Take a look at the examples on MSDN. You basically want to create a column, specify the formula and then add that column to a DataTable. You’ll end up with something like

// Create total column.
DataColumn totalColumn = new DataColumn();
totalColumn.DataType = System.Type.GetType("System.Decimal");
totalColumn.ColumnName = "total";
totalColumn.Expression = "AmountSold + AmountUpgraded";

// Add columns to DataTable.
...
table.Columns.Add(totalColumn);

You don’t need to manually loop through all of the rows, that will be computed for you.