End Sub
    Private Sub TextBox7_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TxtBookAuthor.KeyPress
        Dim strChar As String
        strChar = e.KeyChar

        Select Case strChar
            Case ChrW(System.Windows.Forms.Keys.Enter)
                If checkTextbox(TxtBookAuthor) = False Then
                    display_MsgBox("Please Fill in the field")
                Else
                    If checkTextbox(TxtBookAuthor) = True Then
                        TxtEdition.Focus()
                    End If
                End If
            Case Else
                'dotnothing
        End Select
    End Sub
    Private Sub TextBox8_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TxtEdition.KeyPress
        Dim strChar As String
        strChar = e.KeyChar

        Select Case strChar
            Case ChrW(System.Windows.Forms.Keys.Enter)
                If checkTextbox(TxtEdition) = False Then
                    display_MsgBox("Please Fill in the field")
                Else
                    If checkTextbox(TxtEdition) = True Then
                        TxtPublishdate.Focus()
                    End If
                End If
            Case Else
                'dotnothing
        End Select
    End Sub
    Private Sub TextBox9_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TxtPublishdate.KeyPress
        Dim strChar As String
        strChar = e.KeyChar

        Select Case strChar
            Case ChrW(System.Windows.Forms.Keys.Enter)
                If checkTextbox(TxtPublishdate) = False Then
                    display_MsgBox("Please Fill in the field")
                Else
                    If checkTextbox(TxtPublishdate) = True Then
                        Dim myText As String = TxtPublishdate.Text

                        ComboStatus.Focus()
                    End If
                End If
            Case Else
                'dotnothing
        End Select
    End Sub
    Private Sub ComboboxBox3_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles ComboStatus.KeyPress
        Dim strChar As String
        strChar = e.KeyChar
        Select Case strChar
            Case ChrW(System.Windows.Forms.Keys.Enter)
                If checkCombobox(ComboStatus) = False Then
                    display_MsgBox("請在文本框中輸入信息")
                Else
                    If checkCombobox(ComboStatus) = True Then
                        TxtAdditionDate.Focus()
                    End If
                End If
            Case Else
                '什么也不做
        End Select
    End Sub
    Private Sub TextBox10_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TxtAdditionDate.KeyPress
        Dim strChar As String
        strChar = e.KeyChar

        Select Case strChar
            Case ChrW(System.Windows.Forms.Keys.Enter)
                If checkTextbox(TxtAdditionDate) = False Then
                    display_MsgBox("Please Fill in the field")
                Else
                    If checkTextbox(TxtAdditionDate) = True Then
                        Dim myText2 = TxtAdditionDate.Text
                        BtnAdd.Focus()
                    End If
                End If
            Case Else
                'dotnothing
        End Select
    End Sub
    Function checkCombobox(ByVal t As ComboBox) As Boolean
        If t.Text = "" Then
            Return False
        Else
            Return True
        End If
    End Function
    Function clearFields()
        TxtSN.Text = ""
        TxtISBN.Text = ""
        TxtBookName.Text = ""
        TxtBookCode.Text = ""
        TxtBookType.Text = ""
        TxtBookDes.Text = ""
        TxtBookAuthor.Text = ""
        TxtEdition.Text = ""
        TxtPublishdate.Text = ""
        TxtAdditionDate.Text = ""
        ComboBookCode.Text = ""
        ComboBookType.Text = ""
        ComboStatus.Text = ""
    End Function
    Function checkTextbox(ByVal t As TextBox) As Boolean
        If t.Text = "" Then
            Return False
        Else
            Return True
        End If
    End Function
    Function display_MsgBox(ByVal myMsg As String)
        MsgBox(myMsg, MsgBoxStyle.Information, "圖書館管理系統")
    End Function
    Function add_IntoComboBookCode()
        MyConnection.Open()
        MyCommand = New OleDbCommand("SELECT * FROM BookCode", MyConnection)
        MyReader = MyCommand.ExecuteReader()
        While MyReader.Read
            ComboBookCode.Items.Add(MyReader("Code"))
        End While
        MyConnection.Close()
        MyReader.Close()
        MyCommand.Dispose()
    End Function
    Function add_IntoComboBookType()
        MyConnection.Open()
        MyCommand = New OleDbCommand("SELECT * FROM BookType", MyConnection)
        MyReader = MyCommand.ExecuteReader()
        While MyReader.Read
            ComboBookType.Items.Add(MyReader("Type"))
        End While
        MyConnection.Close()
        MyReader.Close()
        MyCommand.Dispose()
    End Function
    Private Sub ComboBookType_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBookType.SelectedIndexChanged
        MyConnection.Open()
        MyCommand = New OleDbCommand("SELECT * FROM BookType WHERE Type ='" & ComboBookType.Text & "'", MyConnection)
        MyReader = MyCommand.ExecuteReader()
        While MyReader.Read
            TxtBookType.Text = MyReader("Desc")
        End While
        MyConnection.Close()
        MyReader.Close()
        MyCommand.Dispose()
    End Sub
    Private Sub ComboBookCode_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBookCode.SelectedIndexChanged
        MyConnection.Open()
        MyCommand = New OleDbCommand("SELECT * FROM BookCode WHERE Code ='" & ComboBookCode.Text & "'", MyConnection)
        MyReader = MyCommand.ExecuteReader()
        While MyReader.Read
            TxtBookCode.Text = MyReader("Desc1")
        End While
        MyConnection.Close()
        MyReader.Close()
        MyCommand.Dispose()
    End Sub
    Function add_BookIntoDatabase()
        MyConnection.Open()
        MyCommand = New OleDbCommand("INSERT INTO BookDetails VALUES('" & TxtSN.Text & "','" & TxtISBN.Text & "', '" & TxtBookName.Text & "','" & ComboBookCode.Text & "','" & ComboBookType.Text & "','" & TxtBookDes.Text & "','" & TxtBookAuthor.Text & "','" & TxtPublishdate.Text & "','" & TxtEdition.Text & "','" & ComboStatus.Text & "','" & picPath & "','" & TxtAdditionDate.Text & "')", MyConnection)
        MyCommand.ExecuteNonQuery()
        MyConnection.Close()
        MyCommand.Dispose()
    End Function
    ' Function processDate(ByVal dateString As String) As String
    ' Dim strLength As Integer = dateString.Length
    ' Dim tempString1 As String
    ' Dim tempString2 As String
    ' Dim tempString22 As String
    ' Dim tempString3 As String

    ' If strLength > 8 Or strLength < 8 Then
    '     display_MsgBox("Cannot Process Format Of String")
    ' Else
    ' tempString1 = dateString.Chars(0).ToString + dateString.Chars(1).ToString
    '   tempString22 = dateString.Chars(2).ToString + dateString.Chars(3).ToString
    '  tempString2 = get_Month(tempString22)
    '   tempString3 = dateString.Chars(4).ToString + dateString.Chars(5).ToString + dateString.Chars(6).ToString + dateString.Chars(7).ToString
    '    Return tempString1 + "-" + tempString2 + "-" + tempString3
    '   End If

    ' End Function
    'Function get_Month(ByVal oMonth As String) As String
    ' Dim monthString As String = "NIL"

    'Select Case oMonth
    '  Case "01"
    '     monthString = "JAN"
    '  Case "02"
    '      monthString = "FEB"
    '  Case "03"
    '      monthString = "MAR"
    ' Case "04"
    '  monthString = "APR"
    '  Case "05"
    '     monthString = "MAY"

    '  Case "06"
    '   monthString = "JUN"
    ' Case "07"
    '     monthString = "JUL"
    ' Case "08"
    '     monthString = "AUG"
    ' Case "09"
    '     monthString = "SEP"
    '  Case "10"
    '      monthString = "OCT"
    '    Case "11"
    '       monthString = "NOV"
    '   Case "12"
    ' monthString = "DEC"
    '    Case Else
    'do nothing
    '  End Select
    '   Return monthString
    '  End Function


    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnClear.Click
        clearFields()
        TxtSN.Focus()
        Beep()
    End Sub
    Function checkSpecificFields() As Boolean
        If TxtSN.Text = "" Or TxtISBN.Text = "" Or TxtBookName.Text = "" Or TxtBookDes.Text = "" Or TxtBookAuthor.Text = "" Or TxtEdition.Text = "" Or TxtPublishdate.Text = "" Or TxtAdditionDate.Text = "" Then
            Return False
        Else
            Return True
        End If
    End Function
    Private Sub BtnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnAdd.Click
        If checkSpecificFields() = False Then
            display_MsgBox("請在相應的文本框中添加書籍信息")
        Else
            If checkSpecificFields() = True Then
                add_BookIntoDatabase()
                Beep()
                TxtSN.Focus()
                display_MsgBox("書籍信息已被添加到數據庫")
                clearFields()
            End If
        End If
    End Sub
    Function checkIfAlreadyExists() As Boolean
        MyConnection.Open()
        MyCommand = New OleDbCommand("SELECT * FROM BookDetails WHERE SN ='" & TxtSN.Text & "'", MyConnection)
        MyReader = MyCommand.ExecuteReader()
        Dim TempString As String
        While MyReader.Read
            TempString = MyReader("SN")
        End While
        MyConnection.Close()
        MyReader.Close()
        MyCommand.Dispose()
        If TxtSN.Text = TempString Then
            Return True
        Else
            If TxtSN.Text <> TempString Then
                Return False
            End If
        End If
    End Function

    Private Sub OpenFileDialog1_FileOk1(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles OpenFileDialog1.FileOk
        Dim width As Integer = 100
        Dim height As Integer = 100
        bookPicture = System.Drawing.Bitmap.FromFile(OpenFileDialog1.FileName)
        picPath = OpenFileDialog1.FileName.ToString
        PictureBox1.Image = bookPicture
    End Sub
End Class