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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!
    ------------------------------
     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

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  • 原文地址:https://www.cnblogs.com/sishierfei/p/1610389.html
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