派工表有日期列，我想统计时按月统计，工号（）的平均计分金额。下面代码中怎么添加日期按月统计。？

Dim dt As DataTable
 Dim dtb As New  DataTableBuilder("统计表")
dtb.AddDef("工号", Gettype(String), 16)
 dtb.AddDef("计分金额", Gettype(Double))
 dt = dtb.Build()
 \'开始逐行累加统计
Dim lst As  New  Dictionary(of String ,DataRow) \'定义一个字典,用于检索每个员工在统计表中对应的行
For Each dr1 As DataRow In DataTables("派工").DataRows
     If dr1.IsNull("工号") = False Then \'如果工号列不为空
        Dim nms() As String = dr1("工号").Split(",") \'将工号列内容拆分成数组
        Dim v As Double = dr1("计分金额") / nms.Length \'获得平均之后每个工号的生产计分金额
        For Each nm As String In nms  \'遍历参与加工此产品的每个工号
            Dim  dr2 As  DataRow
             If  lst.ContainsKey(nm) \'如果集合中包括此工号对应的行
                dr2=  lst(nm) \'将此行赋值给变量dr2
             Else
                 dr2 = dt.AddNew() \'否则增加一行.
                 dr2("工号") = nm  \'新增行的工号列设置为此工号
                lst.add(nm,dr2) \'将新增行添加到字典中,以便接下来检索
            End If
             dr2("计分金额") = dr2("计分金额") + v  \'加上平均后的产量
        Next
     End If
 Next
Tables("窗口3_统计表").DataSource = DataTables("统计")

\'设置月份的列宽
For Each c As Col In Tables("窗口3_统计表").Cols
     If c.DataCol.IsNumeric Then
        c.Width = 58
     End If
Next

立即马上，就传

Dim sd As Date = "2016-04-10"
Dim ed As Date = "2016-05-20"

Dim dt As DataTable
Dim dtb As New  DataTableBuilder("统计表")
dtb.AddDef("工号", Gettype(String), 16)
dtb.AddDef("计分金额", Gettype(Double))
dt = dtb.Build()
\'开始逐行累加统计
Dim lst As  New  Dictionary(of String ,DataRow) \'定义一个字典,用于检索每个员工在统计表中对应的行
For Each dr1 As DataRow In DataTables("派单").Select("日期>=#" & sd & "# and 日期 <#" & ed.AddDays(1) & "#")
    If dr1.IsNull("工号") = False Then \'如果工号列不为空
        Dim nms() As String = dr1("工号").Split(",") \'将工号列内容拆分成数组
        Dim v As Double = dr1("计分金额") / nms.Length \'获得平均之后每个工号的生产计分金额
        For Each nm As String In nms  \'遍历参与加工此产品的每个工号
            Dim  dr2 As  DataRow
            If  lst.ContainsKey(nm) \'如果集合中包括此工号对应的行
                dr2=  lst(nm) \'将此行赋值给变量dr2
            Else
                dr2 = dt.AddNew() \'否则增加一行.
                dr2("工号") = nm  \'新增行的工号列设置为此工号
                lst.add(nm,dr2) \'将新增行添加到字典中,以便接下来检索
            End If
            dr2("计分金额") = dr2("计分金额") + v  \'加上平均后的产量
        Next
    End If
Next

http://www.foxtable.com/help/topics/2720.htm

Dim sd As Date = e.Form.Controls("DateTimePicker1").Value
Dim ed As Date = e.Form.Controls("DateTimePicker2").Value

Dim dt As DataTable
Dim dtb As New  DataTableBuilder("统计表")
dtb.AddDef("员工", Gettype(String), 16)
dtb.AddDef("计分金额", Gettype(Double))
dt = dtb.Build()
\'开始逐行累加统计
Dim lst As  New  Dictionary(of String ,DataRow) \'定义一个字典,用于检索每个员工在统计表中对应的行
For Each dr1 As DataRow In DataTables("派单").Select("日期>=#" & sd & "# and 日期 <#" & ed.AddDays(1) & "#")
    If dr1.IsNull("员工") = False Then \'如果员工列不为空
        Dim nms() As String = dr1("员工").Split(",") \'将员工列内容拆分成数组
        Dim v As Double = dr1("计分金额") / nms.Length \'获得平均之后每个员工的生产计分金额
        For Each nm As String In nms  \'遍历参与加工此产品的每个员工
            Dim  dr2 As  DataRow
            If  lst.ContainsKey(nm) \'如果集合中包括此员工对应的行
                dr2=  lst(nm) \'将此行赋值给变量dr2
            Else
                dr2 = dt.AddNew() \'否则增加一行.
                dr2("员工") = nm  \'新增行的员工列设置为此员工
                lst.add(nm,dr2) \'将新增行添加到字典中,以便接下来检索
            End If
            dr2("计分金额") = dr2("计分金额") + v  \'加上平均后的产量
        Next
    End If
Next
e.Form.Controls("统计表").Table.DataSource = DataTables("统计表")