If e.DataCol.Name = "请款日期" Then
If e.DataRow.IsNull("请款日期") Then
e.DataRow("请款单号") = Nothing
Else
Dim d As Date = e.DataRow("请款日期")
Dim y As Integer = d.Year
Dim fd As Date = New Date(y,1,1) '获得该年的第一天
Dim ld As Date = fd.addyears(1)
Dim bh As String = Format(d,"yyyy") '生成编号的前4位年.
If e.DataRow("请款单号").StartsWith(bh) = False '如果编号的前4位不符
Dim max As String
Dim idx As Integer
max = e.DataTable.Compute("Max(请款单号)","请款日期 >= #" & fd & "# And 请款日期 < #" & ld & "# And [_Identify] <> " & e.DataRow("_Identify")) '取得该年的最大编号
If max > "" Then '如果存在最大编号
idx = CInt(max.Substring(4,3)) + 1 '获得最大编号的后三位顺序号,并加1
Else
idx = 1 '否则顺序号等于1
End If
e.DataRow("请款单号") = bh & Format(idx,"000")
End If
End If
End If