Function selectlogon(ByVal User As Entity.logonEntity) As Entity.logonEntity Dim cmd_logon As New sqlCommand '实例化一个命令对象 Dim sqlconnection_logon = New sqlConnection(DbUtil.sqlConcectStr) '实例化带条件的一个数据库连接对象 cmd_logon.Connection = sqlconnection_logon '创建连接命令 sqlconnection_logon.Open() '执行连接，将数据库打开 '建立查询语句 cmd_logon.CommandText = "SELECT * FROM T_logon WHERE CardID = '" & User.CardID & "' " Dim reader As sqlClient.sqlDataReader '建立读数据对象 reader = cmd_logon.ExecuteReader '对象逐条读 Dim users As New Entity.logonEntity While (reader.Read()) '循环读数据 If users Is Nothing Then users = New Entity.logonEntity End If users.ID = reader.GetValue(reader.GetOrdinal("UserID")) '读取数据，赋给新实体 users.CardID = reader.GetValue(reader.GetOrdinal("CardID")) users.UserName = reader.GetValue(reader.GetOrdinal("UserName")) users.Sex = reader.GetValue(reader.GetOrdinal("Sex")) users.Department = reader.GetValue(reader.GetOrdinal("Department")) users.Grade = reader.GetValue(reader.GetOrdinal("Grade")) users.InCash = reader.GetValue(reader.GetOrdinal("InCash")) End While sqlconnection_logon.Close() Return users End Function
@H_301_0@（2）插入数据 @H_301_0@（采用：参数法）
Function InsertUp_Doing(ByVal User As Entity.MainEntity) As Boolean
Dim cmd_insert_updoing As New sqlCommand
Dim sqlconnection_updoing As New sqlConnection(DbUtil.sqlConcectStr)
cmd_insert_updoing.Connection = sqlconnection_updoing
'插入语句
cmd_insert_updoing.CommandText = "INSERT INTO T_Updoing (CardID) Values(@CardID)"
'参数法
cmd_insert_updoing.Parameters.Add(New sqlParameter("@CardID",User.CardID))
sqlconnection_updoing.Open()
cmd_insert_updoing.ExecuteNonQuery()
sqlconnection_updoing.Close()
Return True
End Function
（3）更新数据 @H_301_0@（采用：拼接字符串 法）
Function update_updown(ByVal User As Entity.MainEntity) As Boolean
Dim OK_NO_updown As Boolean
Dim cmd_update_updown As New sqlCommand
Dim sqlconnection_updown As New sqlConnection(DbUtil.sqlConcectStr)
'根据“学号”、“状态”条件更新
cmd_update_updown.Connection = sqlconnection_updown
cmd_update_updown.CommandText = "UPDATE T_UpDown " & _
"SET Downdatetime = @Downdatetime,Downtime = @Downtime,Consumetime = @Consumetime" & _
",ConsumeCash = @ConsumeCash,Remaincash = @Remaincash " & _
"WHERE CardID = '" & User.CardID & "'"
cmd_update_updown.CommandType = CommandType.Text
sqlconnection_updown.Open() '打开连接
'添加参数
cmd_update_updown.Parameters.Add(New sqlParameter("@Downdatetime",User.Downdatetime))
cmd_update_updown.Parameters.Add(New sqlParameter("@Downtime",User.Downtime))
cmd_update_updown.Parameters.Add(New sqlParameter("@Consumetime",User.Timeconsume))
cmd_update_updown.Parameters.Add(New sqlParameter("@ConsumeCash",User.Cashconsume))
cmd_update_updown.Parameters.Add(New sqlParameter("@Remaincash",User.Cashremain))
cmd_update_updown.ExecuteNonQuery()
sqlconnection_updown.Close()
Return OK_NO_updown = True
End Function
@H_301_0@（4）删除数据
@H_301_0@（采用：拼接字符串法[CardID =' " & User.CardID & " ' ]）
Function deleteUp_doing(ByVal User As Entity.MainEntity) As Boolean
Dim OK_NO_down As Boolean
Dim cmd_delete_updoing As New sqlCommand
Dim sqlconnection_delectupdoing As New sqlConnection(DbUtil.sqlConcectStr)
sqlconnection_delectupdoing.Open()
cmd_delete_updoing.Connection = sqlconnection_delectupdoing
cmd_delete_updoing.CommandText = "DELETE FROM T_Updoing WHERE CardID ='" & User.CardID & "'"
cmd_delete_updoing.ExecuteNonQuery()
sqlconnection_delectupdoing.Close()
Return OK_NO_down = True
End Function
@H_301_0@ 在VB.NET中，与我之前使用一年前使用VB相比，多了用参数法。查了一些资料，告知，用参数法能减少错误的产生，增强安全性。 @H_301_0@ 上面的代码中，传参采用的是传实体的方式。在VB.NET中，与实体代码更具自动性，与C#中实体相比，这也体现了一定的优越性。