主题：按条件统计数据代码问题

蓝老师的代码如下

Dim rrbh As WinForm.TextBox = e.Form.Controls("RYBH")
Dim bmbm As WinForm.TextBox = e.Form.Controls("BMBM")
Dim khbm As WinForm.TextBox = e.Form.Controls("KHBM")
Dim filter As String = "1=1"
If rrbh.text > "" Then
    filter &= " and 人员编号 = '" & rrbh.text & "'"
End If
If bmbm.text > "" Then
    filter &= " and 部门编码 = '" & bmbm.text & "'"
End If
If khbm.text > "" Then
    filter &= " and 客户编码 = '" & khbm.text & "'"
End If
Dim t1 As DataTable = DataTables("收款明细表")
Dim t2 As DataTable = DataTables("付款明细表")

Dim sum1 As Double = t1.Compute("sum(数量)", filter)
Dim sum2 As Double = t1.Compute("sum(金额)", filter)
Dim sum3 As Double = t2.Compute("sum(数量)", filter)
Dim sum4 As Double = t2.Compute("sum(金额)", filter)

e.Form.Controls("SKSL").text = sum1
e.Form.Controls("fkSL").text = sum3
e.Form.Controls("SKJE").text = sum2
e.Form.Controls("FKJE").text = sum4
e.Form.Controls("SYSL").text = sum1-sum3
e.Form.Controls("SYJE").text = sum2-sum4