VB.Net机房收费系统(三层)——用datagirdview 控件显示数据库
机房收费系统中,对于其需求而言,其中少不了要用到datagridview控件来显示一些从数据库中检索到的信息。现在用其中的一个实例来实现以下系统中查询用户充值记录的用例。 以前自己学习的三层资料中,得到的一个学习信息是在三层中,应该把业务逻辑层作为出发点,然后进行功能的实现。或许一个人一个感觉吧,我总是感觉从数据访问层出发,更符合我们的思维逻辑,从而方便业务功能的实现。对于用户充值记录。 Dal数据访问层:
ImportsSystem.Data.SqlClient Public Function Checkrecord(ByVal Student AsEntity.RechargeRecord) As DataTable Dim conn As SqlConnection = NewSqlConnection(DAL.DbConnection.Constr) Dim da As New SqlDataAdapter Dim dst As New DataSet Dim dt As New DataTable conn.Open()
Dim sql As String = "select *from Recharge_Info where CardID='"& Student.CardID & "'" Dim cmd As SqlCommand = NewSqlCommand(sql,conn)
da.SelectCommand = cmd da.Fill(dst,"Recharge_Info") dt =dst.Tables("Recharge_Info") conn.Close() Return dt End Function BLL业务逻辑层:
PublicFunction CheckRecord(ByVal Student As Entity.RechargeRecord) As DataTable Dim dalRechargeRecord As NewDAL.RechargeRecordDAL Dim dt As New DataTable dt =dalRechargeRecord.Checkrecord(Student) Return dt End Function
UI用户界面层: Dim entityStuRecordAs New Entity.RechargeRecord entityStuRecord.CardID = txtCardID.Text Dim bllRechargeRecord As NewBLL.RechargeRecord DataGridView1.DataSource =bllRechargeRecord.CheckRecord(entityStuRecord)
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