How to use different DataFieldUnboundExpressionMode for different fields in the same PivotGridControl

In this example, the DataFieldUnboundExpressionMode property is set to UseSummaryValues. For fields where it is required to calculate unbound values using the standard behavior the CustomUnboundFieldData event is handled. The ExpressionEvaluator.Evaluate method is used to calculate a summary value based on an unbound expression that has been passed.
Since the CustomUnboundFieldData event is not raised for fields with a predefined UnboundExpression Property, unbound expressions for these fields are stored in separate dictionaries, and their UnboundExpression Property is cleared.