主题：统计

Forms("录入窗口").Close()

DataTables("收购").LoadFilter = "[日期] Between #" & vars("ddate") & "# And #" & vars("vdate") & "#"

DataTables("收购").Load()

DataTables("销售").LoadFilter = "[日期] Between #" & vars("ddate") & "# And #" & vars("vdate") & "#"

DataTables("销售").Load()

Dim drs As List(Of DataRow)

drs = DataTables("收购").Select("[重量] > 0")

Dim dr As List(Of DataRow)

dr = DataTables("销售").Select("[重量] > 0")

If vars("ddate") > vars("vdate") Or drs.count = 0 Or dr.count = 0 Then

    Dim aa As WinForm.DateTimePicker = e.Form.Controls("起始日期")

    Dim bb As WinForm.DateTimePicker = e.Form.Controls("终止日期")

    Dim cc As WinForm.TextBox = e.Form.Controls("收购头数")

    Dim dd As WinForm.TextBox = e.Form.Controls("收购重量")

    Dim ee As WinForm.textBox = e.Form.Controls("收购金额")

    Dim ff As WinForm.TextBox = e.Form.Controls("销售头数")

    Dim gg As WinForm.TextBox = e.Form.Controls("销售重量")

    Dim hh As WinForm.TextBox = e.Form.Controls("销售金额")

    Dim zz As WinForm.TextBox = e.Form.Controls("商品损耗")

    aa.Text=""

    bb.Text=""

    cc.Text=""

    dd.text=""

    ee.Text=""

    ff.Text=""

    gg.Text=""

    hh.text=""

    zz.text=""

    MessageBox.Show("统计日期范围收购或销售数据为零!")

    

ElseIf vars("ddate") <= vars("vdate") And drs.count > 0 And dr.count > 0 Then

    vars("Suma") =  DataTables("收购").Compute("Sum(头数)", "[日期] >= #" & Vars("ddate") & "# and [日期] <= #" & Vars("vdate") & "#")

    vars("Sumb") =  DataTables("收购").Compute("Sum(重量)", "[日期] >= #" & Vars("ddate") & "# and [日期] <= #" & Vars("vdate") & "#")

    vars("Sumc") =  DataTables("收购").Compute("Sum(收购金额)","[日期] >= #" & Vars("ddate") & "# and [日期] <= #" & Vars("vdate") & "#")

    vars("Sumaa") =  DataTables("销售").Compute("Sum(份数)", "[日期] >= #" & Vars("ddate") & "# and [日期] <= #" & Vars("vdate") & "#")

    vars("Sumbb") =  DataTables("销售").Compute("Sum(重量)", "[日期] >= #" & Vars("ddate") & "# and [日期] <= #" & Vars("vdate") & "#")

    vars("Sumcc") =  DataTables("销售").Compute("Sum(金额)", "[日期] >= #" & Vars("ddate") & "# and [日期] <= #" & Vars("vdate") & "#")

    vars("xx7") =  DataTables("收购").Compute("Sum(商品损耗)", "[日期] >= #" & Vars("ddate") & "# and [日期] <= #" & Vars("vdate") & "#")

End If

Dim dl As List(Of DataRow)

dl = DataTables("收购").Select("[商品损耗] > 0")

If dl.count = 0 Then

    MessageBox.Show("商品损耗为零!")

Else

    If vars("suma") = vars("sumaa") Then

        Forms("统计窗口").controls("label13").text = "收购与销售头数相同."

    Else

        Forms("统计窗口").controls("label13").text = "收购与销售头数不相同."

    End If

    If vars("sumb") = vars("sumbb") +vars("xx7") Then

        Forms("统计窗口").controls("label14").text = "收购与销售重量相同."

    Else

        Forms("统计窗口").controls("label14").text = "收购与销售重量不相同."

    End If

End If

.NET Framework 版本：2.0.50727.3655

Foxtable 版本：2014.5.6.1

错误所在事件：窗口,统计窗口,Button1,Click

详细错误信息：

Cannot set Column 'xx7' to be null. Please use DBNull instead.

if  Vars("ddate") <> "" andalso Vars("vdate") <> "" then