主题：获取编号的方法中的错误

Public Function GetSystemDate() As Date

Dim aD As Date

Dim cmd1 As New SQLCommand

'设置数据源名称

cmd1.C

cmd1.commandText = "Select getdate()"

ad = cmd1.ExecuteScalar

Return ad

End Function

'编码规范类型名    前缀  日期格式  数据位数

Public Function GetSystemBM(bmType As String,byval PF As String,byval DFormat As String ,byval sNum As Integer) As String

Dim bm As String

Dim dt As DataTable

Dim Key As Integer

Dim Adate As String

Dim aWhere As String

Dim Astr As new String("0",snum)

Dim sDate As Date

Dim cmd1 As New SQLCommand

Dim cmd2 As New SQLCommand

sdate=GetSystemDate()

'设置数据源名称

cmd1.C

cmd2.C

'检查是否存在此编码规范 如果不存在 则添加

cmd1.commandText = "Select Count(*) From [系统编码] Where [前缀] = '" & PF & "'"

If cmd1.ExecuteScalar = 0 Then '如果编号表不存在前缀的行,那么增加一行

    cmd1.commandtext = "Insert Into 系统编码(前缀, 顺序号,日期,日期格式) Values('" & PF & "',1,'" & format(sdate,DFormat) & "','" &  DFormat & "')"

    cmd1.ExecuteNonQuery

End If

'获取并更新编码规范

cmd1.commandText = "Select [顺序号][日期][日期格式] From [系统编码] Where [前缀] = '" & PF & "'"

Do

    dt = cmd1.ExecuteReader()'从后台获得顺序号,日期,日期格式

    MessageBox.SHOW (“下面出错啦”)

    If format(sDate,dt.DataRows(0)("日期格式"))<>dt.DataRows(0)("日期")  Then

        key=1

        Adate=dt.DataRows(0)("日期")

    Else

        key=dt.DataRows(0)("顺序号") +1

        Adate= format(sDate,  dt.DataRows(0)("日期格式"))

    End If   

    

    aWhere= "[顺序号] = " & dt.DataRows(0)("顺序号") & " And [日期] = '" & dt.DataRows(0)("日期")  & "' And [前缀] = '" & pf & "'"

    cmd2.commandText = "Update [系统编码] Set [顺序号] = " & Key  & ",[日期] = " & Adate & " Where " & aWhere

    If cmd2.ExecuteNonQuery() > 0 Then '更新顺序号

        Exit Do '更新成功则退出循环

    End If

Loop

'返回编码

bm = PF & Adate & Format(Key,Astr)

Return bm

End Function

请教专家怎么解决