שיטה נוספת
אם תשתמש ב-DataTable תוכל לבצע DataTable.Compute
Computes the given expression on the current rows that pass the filter criteria. [Visual Basic] Public Function Compute( _ ByVal expression As String, _ ByVal filter As String _ ) As Object [C#] public object Compute( string expression, string filter ); Parameters expression The expression to compute. filter The filter to limit the rows that evaluate in the expression. Return Value An Object, set to the result of the computation. Remarks The expression parameter requires an aggregate function. For example, the following is a legal expression: Count(Quantity) But this expression is not: Sum (Quantity * UnitPrice) If you must perform an operation on two or more columns, you should create a DataColumn, set its Expression property to an appropriate expression, and use an aggregate expression on the resulting column. In that case, given a DataColumn with the name "total," and the Expression property set to: "Quantity * UnitPrice" The expression argument for the Compute method would then be: Sum(total) The second parameter filter determines which rows are used in the expression. For example, if the table contains a date column named "colDate", you could limit the rows with the following expression: colDate > 1/1/99 AND colDate < 17/1/99 For rules on creating expressions for both parameters, see the Expression property of the DataColumn class.
