d_admininfo.vb

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'建立D_AdminInfo操作类，来实现对用户登陆信息数据库的操作
Public Class D_AdminInfo
    Private Conn As MdbConnObj
    Public Sub New()
        Conn = New MdbConnObj
    End Sub

#Region "过程函数说明： 检查用户名和密码是否正确"
    Public Function LoginCheck(ByVal C As S_AdminInfo, ByRef StrError As String) As S_AdminInfo
        Try
            If Not Conn.Connect Then '检查数据连接对象是否成功
                StrError = Conn.LastError '这个消息保存了数据库连接的错误消息
                Exit Function
            End If
            Dim OleDbComm As New System.Data.OleDb.OleDbCommand '创建命令对象
            '设置Sql命令以及关联Sql连接
            With OleDbComm
                .CommandText = "Select LoginName,LoginPwd from Admin  Where LoginName =? "
                .Connection = Conn.ConnObj
                .Parameters.Add(New System.Data.OleDb.OleDbParameter("LoginName", CType(130, System.Data.OleDb.OleDbType), 50, "LoginName")) '添加参数并为参数设置值：LoginName
                .Parameters("LoginName").Value = C.LoginName
            End With
            Dim OleDbDr As System.Data.OleDb.OleDbDataReader
            OleDbDr = OleDbComm.ExecuteReader
            If OleDbDr.Read Then '如果获取了数据
                C.LoginName = OleDbDr("LoginName")
                C.LoginPwd = OleDbDr("LoginPwd")
                LoginCheck = C
            Else
                LoginCheck = Nothing '如果没有找到记录，也返回Nothing 
            End If
        Catch ex As Exception
            StrError = ex.Message '保存错误的消息
            LoginCheck = Nothing '如果遇到错误，就返回Nothing
        Finally
            Conn.ConnObj.Close() '管理数据连接
        End Try
    End Function
#End Region

#Region "过程函数说明： 修改用户密码"
    Public Function EditPwd(ByVal S As S_AdminInfo, ByRef StrError As String) As Boolean
        Try
            '检查数据连接对象是否成功
            If Not Conn.Connect Then
                StrError = Conn.LastError
                Return False
            End If
            '创建命令对象
            Dim OleDbComm As New System.Data.OleDb.OleDbCommand
            '为命令对象设置Sql字符串
            With OleDbComm
                .CommandText = "UPDATE Admin SET LoginPwd = ?   Where LoginName =? "
                .Connection = Conn.ConnObj '添加参数并为参数设置值：LoginPwd
                .Parameters.Add(New System.Data.OleDb.OleDbParameter("LoginPwd", CType(130, System.Data.OleDb.OleDbType), 50, "LoginPwd")).Value = S.LoginPwd '添加参数并为参数设置值：LoginName
                .Parameters.Add(New System.Data.OleDb.OleDbParameter("LoginName", CType(130, System.Data.OleDb.OleDbType), 50, "LoginName")).Value = S.LoginName
                .ExecuteNonQuery()
            End With
            EditPwd = True
        Catch ex As Exception
            StrError = ex.Message
            EditPwd = False '如果遇到错误，就返回Nothing
        Finally
            Conn.ConnObj.Close() '管理数据连接
        End Try
    End Function
#End Region

#Region "过程函数说明： 添加新用户"
    Public Function AddGuest(ByVal C As S_AdminInfo, ByRef StrError As String) As Boolean
        Try
            '检查数据连接对象是否成功
            If Not Conn.Connect Then
                StrError = Conn.LastError
                Return False
            End If

            '创建命令对象
            Dim OleDbComm As New System.Data.OleDb.OleDbCommand
            '为命令对象设置Sql字符串
            OleDbComm.CommandText = "INSERT INTO Admin (LoginName,LoginPwd) VALUES (?,?)"
            OleDbComm.Connection = Conn.ConnObj

            '添加参数并为参数设置值：LoginName
            OleDbComm.Parameters.Add(New System.Data.OleDb.OleDbParameter("LoginName", CType(130, System.Data.OleDb.OleDbType), 50, "LoginName"))
            OleDbComm.Parameters("LoginName").Value = C.LoginName

            '添加参数并为参数设置值：LoginPwd
            OleDbComm.Parameters.Add(New System.Data.OleDb.OleDbParameter("LoginPwd", CType(130, System.Data.OleDb.OleDbType), 50, "LoginPwd"))
            OleDbComm.Parameters("LoginPwd").Value = C.LoginPwd


            OleDbComm.ExecuteNonQuery()
            AddGuest = True
        Catch ex As Exception
            StrError = ex.Message
            AddGuest = False '如果遇到错误，就返回Nothing
        Finally
            Conn.ConnObj.Close() '管理数据连接
        End Try
    End Function
#End Region

#Region "过程函数说明： 选择所有用户"
    Public Function SelectGuest(ByRef StrError As String) As System.Data.DataSet
        '利用Select命令返回包含结果的DateSet
        Try
            If Not Conn.Connect Then '检查数据连接对象是否成功
                StrError = Conn.LastError '这个消息保存了数据库连接的错误消息
                Return Nothing '如果数据库连接不正常的话，就返回Nothing
            End If
            Dim OleDbComm As New System.Data.OleDb.OleDbCommand '创建命令对象
            Dim OleDbAdap As New System.Data.OleDb.OleDbDataAdapter
            Dim OleDataSet As New System.Data.DataSet 'Dataset
            OleDbAdap.SelectCommand = OleDbComm '关联OleDbCommand 和 OleDbDataAdapter
            '设置Sql命令以及关联Sql命令
            OleDbComm.CommandText = "Select LoginName from Admin "
            OleDbComm.Connection = Conn.ConnObj

            OleDbAdap.Fill(OleDataSet)
            SelectGuest = OleDataSet
        Catch ex As Exception
            StrError = ex.Message '保存的错误消息
            SelectGuest = Nothing
        Finally
            Conn.ConnObj.Close()
        End Try
    End Function
#End Region


#Region "过程函数说明： 删除用户"
    Public Function DelGuest(ByVal C As S_AdminInfo, ByRef StrError As String) As Boolean
        Try
            '检查数据连接对象是否成功
            If Not Conn.Connect Then
                StrError = Conn.LastError
                Return False
            End If

            '创建命令对象
            Dim OleDbComm As New System.Data.OleDb.OleDbCommand
            '为命令对象设置Sql字符串
            OleDbComm.CommandText = "Delete From Admin  Where LoginName =? "
            OleDbComm.Connection = Conn.ConnObj

            '添加参数并为参数设置值：LoginName
            OleDbComm.Parameters.Add(New System.Data.OleDb.OleDbParameter("LoginName", CType(130, System.Data.OleDb.OleDbType), 50, "LoginName"))
            OleDbComm.Parameters("LoginName").Value = C.LoginName


            OleDbComm.ExecuteNonQuery()
            DelGuest = True
        Catch ex As Exception
            StrError = ex.Message
            DelGuest = False '如果遇到错误，就返回Nothing
        Finally
            Conn.ConnObj.Close() '管理数据连接
        End Try
    End Function
#End Region

End Class