主题：[求助]如何实现双击目录树节点，求子节点某列之和的最小值在窗口的textbox控件内显示

动态合成条件求值即可，比如

Dim d As Date = new Date(2012, 1, 1)

Dim Filter = "日期 >= #" & d & "# and 日期 < #" & d.AddYears(1) & "#"

Dim sum = DataTables("订单").Compute("sum(金额)", filter)

Dim max = DataTables("订单").Compute("max(金额)", filter)

Dim min = DataTables("订单").Compute("min(金额)", filter)

msgbox(sum)

msgbox(max)

magbox(min)