frm_changereaderpass.vb

是关于图书管理系统的用vb.net 和access开发的

Imports System.Data.OleDb
Public Class frm_changeReaderPass


    Dim myConnection As New OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0; Data source=D:\library.mdb")
    Dim myCommand As OleDbCommand
    Dim myReader As OleDbDataReader

    Private Sub frm_changeReaderPass_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        readerNotxt.Focus()
    End Sub

   Private Sub oldpasstxt_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles oldPasstxt.KeyPress
        If e.KeyChar = ChrW(System.Windows.Forms.Keys.Enter) Then
            checkValidReader()
        End If
    End Sub
    Sub checkValidReader()
        Dim rNo As String = ""
        Dim Opass As String = ""


        myConnection.Open()
        myCommand = New OleDbCommand("select * from ReaderDetails where ReaderNo = '" & readerNotxt.Text & _
           "'", myConnection)
        myReader = myCommand.ExecuteReader()

        While myReader.Read
            rNo = myReader("ReaderNo")
            Opass = myReader("Password")
        End While

        myConnection.Close()
        myReader.Close()
        myCommand.Dispose()

        If rNo = "" Then
            MsgBox("Invalid Reader No!")
            readerNotxt.Clear()
            oldPasstxt.Clear()
            readerNotxt.Focus()

        Else

            If oldPasstxt.Text = Opass Then
                newPasstxt.Focus()
            Else

                MsgBox("Invalid Reader Password!")
                oldPasstxt.Focus()
                oldPasstxt.SelectAll()

            End If
        End If
    End Sub


    Private Sub newpasstxt_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles newPasstxt.KeyPress
        If e.KeyChar = ChrW(System.Windows.Forms.Keys.Enter) Then
            If newPasstxt.Text = "" Then
                MsgBox("password can not be empty!")
                newPasstxt.Focus()
            Else
                againtxt.Focus()

            End If
        End If
    End Sub

  

    Private Sub okbt_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles okbt.Click
        If checkPasswordSame() Then
            changePassword()
        Else
            MsgBox("The 2nd input new password is not as same as the 1st one!")
            againtxt.Focus()
            againtxt.SelectAll()
        End If

    End Sub

    Function checkPasswordSame() As Boolean
        Dim firstStr As String = newPasstxt.Text
        Dim secondStr As String = againtxt.Text

        If firstStr.Equals(secondStr) Then
            Return True
        Else
            Return False
        End If
    End Function
    Sub changePassword()

        myConnection.Open()
        myCommand = New OleDbCommand("Update ReaderDetails set [Password]='" & newPasstxt.Text & _
        "' where readerNo='" & readerNotxt.Text & "'", myConnection)


        myCommand.ExecuteNonQuery()
        MsgBox("Change password success!")



        myConnection.Close()
        myCommand.Dispose()
    End Sub

    Private Sub exitbt_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exitbt.Click
        Me.Close()

    End Sub

    Private Sub resetbt_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles resetbt.Click
        readerNotxt.Clear()
        oldPasstxt.Clear()
        newPasstxt.Clear()
        againtxt.Clear()

    End Sub
End Class