主题：按日设置加载树和筛选树

窗口AfterLoad事件：

Dim cmd As New SQLCommand
Dim dt As DataTable
cmd.CommandText = "SELECT DISTINCT Year(日期) As 年, Month(日期) As 月,Day(日期) As 日 From {订单}"
dt = cmd.ExecuteReader()
Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")
trv.BuildTree(dt, "年|月|日")

目录树NodeMouseClick事件：

Dim Value()As String
Dim Filter As String
Dim d1 As Date
Dim d2 As Date
Value = e.Node.FullPath.Split("\")
Select Case e.Node.Level
    Case 0
        Dim y As Integer = value(0)
        d1 = New Date(y,1,1) '取得该年的第一天
        d2 = new Date(y,12,31) '取得该年的最后一天
        Filter = "日期 >= #" & d1 & "# And 日期 <= #" & d2 & "#"
    Case 1
        Dim y As Integer = value(0)
        Dim m As Integer = value(1)
        d1 = New Date(y, m, 1) '取得该月的第一天
        d2 = new Date(y, m, Date.DaysInMonth(y,m)) '取得该月的最后一天
        Filter = "日期 >= #" & d1 & "# And 日期 <= #" & d2 & "#"
    Case 2
        Dim y As Integer = value(0)
        Dim m As Integer = value(1)
        Dim d As Integer = Value(2)
        Dim dt As new Date(y,m,d)
        Filter = "日期 = #" & dt & "#"
End Select
Tables("订单").Filter = Filter