Dim ksmc As String = e.Form.Controls("ComboBox01").text
DataTables("学生成绩库").LoadFilter = "[考试名称] = '" & ksmc & "'"
DataTables("学生成绩库").Load()
Dim vals() As Double = {0.2,0.5,0.9}
Dim nms() As String = {"政治","语文","数学","英语"}
Dim cnt As Integer = DataTables("学生成绩库").DataRows.count
For Each nm As String In nms
Dim drs As List (of DataRow) = DataTables("学生成绩库").Select(nm & " <> 0 And " & nm & " Is not null", nm & " Desc")
Dim dn As String = nm & "等级"
For i As Integer = 0 To drs.count - 1
Dim v As Double = i /cnt
If v > vals(2) Then
drs(i)(dn) = "D"
ElseIf v > vals(1) Then
drs(i)(dn) = "C"
ElseIf v > vals(0) Then
drs(i)(dn) = "B"
Else
drs(i)(dn) = "A"
End If
Next
DataTables("学生成绩库").ReplaceFor("等级", "缺考", nm & " = 0 or " & nm & " Is null")
Next