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ID的动态添加

一):数据库存储为int型,在textbox里显示“01”,之后根据数据库里ID的情况显示下一行ID,比如,数据库里的ID最大值为“06”,则新打开界面时要在界面上显示“07”:
 
--------------------
写在前面的代码:
  Private ds As New DataSet
    Dim comid1 As Int32
    Dim comid2 As Int32
----------
   Dim sql As String = "select max(表里的ID字段) from 表"
   Dim adt As New OleDbDataAdapter(sql, DBcon)
   ds.Clear()
   adt.Fill(ds)
   comid2 = ds.Tables(0).Rows(0)(0)
   comid2 = comid2 + 1
   Me.TextBox3.Text = comid2
此段代码要写在form_load 和 相应按钮里,一个也不能少!
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 二):数据库存储为char型,在textbox里显示“c01”,之后根据数据库里ID的情况显示下一行ID,比如,数据库里的ID最大值为“c06”,则新打开界面时要在界面上显示“c07”:
--------------------
写在前面的代码:
  Private ds As New DataSet
    Dim comid1 As Int32
    Dim comid2 As Int32
    Dim comchar As String
    Dim comchar1 As String = "c"
    Dim comchar2 As String = "0"
----------
Dim sql1 As String = "select count(表里的ID字段) as cTypeID from 表"
        Dim adt As New OleDbDataAdapter(sql1, DBcon)
        ds.Clear()
        adt.Fill(ds)
        comid1 = ds.Tables(0).Rows(0)(0)
        comid1 = comid1 + 1
        If comid1 <= 9 Then
            comchar = comchar1 & comchar2 & comid1
        Else
            comchar = comchar1 & comid1
        End If
        Me.TextBox1.Text = comchar
此段代码要写在form_load 和 相应按钮里,一个也不能少!
------------------------------
三):数据库存储为char型,在textbox里显示“c01001”,之后根据数据库里ID的情况显示下一行ID,要根据下拉菜单选择表一里的name,再将其对应的ID(c01)显示在textbox里,后面的“001”为自增。(此代码的运行结果为后面三位一直在自增,即选择了c01001之后只能选择c02002,不能选择c02001)
--------------------
写在前面的代码:
  Private ds As New DataSet
  Dim comid As Int32
  Dim comchar As String
  Dim comchar1 As String = "0"
  Dim kuid As String
---------

 DBcon.Open()
        Dim sqlStr As String = "select ID from TMMType where name = '" & Me.ComboBox.SelectedItem & "'"
        Dim adt4 As New OleDbDataAdapter(sqlStr, DBcon)
        ds.Clear()
        adt.Fill(ds)
        DBcon.Close()

        kuid = Trim(CStr(ds.Tables(0).Rows(0).Item("ID")))
        Dim sql1 As String = "select count(ID) as ID from TMMCom"
        Dim adt5 As New OleDbDataAdapter(sql1, DBcon)
        ds5.Clear()
        adt5.Fill(ds5)
        comid = ds5.Tables(0).Rows(0)(0)
        comid = comid + 1
        If comid <= 9 Then
            comchar = kuid & comchar1 & comchar1 & comid
        ElseIf 10 <= comid <= 99 Then
            comchar = kuid & comchar1 & comid
        ElseIf 100 <= comid <= 999 Then
            comchar = kuid & comid
        End If
        Me.TextBox1.Text = comchar

以上代码写在相应按钮和  ComboBox的SelectedIndexChanged 事件里!(必须全写!)

----------------

三)做法二:(三层结构做的)

Public Function GetNewChangeStoreID(ByVal str As String) As String

        Try

            con = New OleDbConnection(constr)

            If con.State = ConnectionState.Open Then

                con.Close()

            End If

            con.Open()

            Dim sqlstr As String = "select Max(right(cID,3)) from TMM_ChangeStore"

            cmd = New OleDbCommand(sqlstr, con)

            Dim read As OleDbDataReader = cmd.ExecuteReader()

            read.Read()

            If Not read.Item(0) Is DBNull.Value Then

                Dim num As Integer = read.Item(0)

                Return "D" & str & (num + 1).ToString("D3")

            Else

                Return "D" & str & "001"

            End If

        Catch ex As Exception

            MsgBox(ex.Message.ToString)

        Finally

            If con.State = ConnectionState.Open Then

                con.Close()

            End If

        End Try

    End Function

posted on 2009-11-25 13:56  似是而非  阅读(445)  评论(0编辑  收藏  举报