lendbook.aspx.vb

图书借阅系统！ASP.NET实现的

Imports System.Data.SqlClient
Public Class LendBook
    Inherits System.Web.UI.Page

#Region " Web 窗体设计器生成的代码 "

    '该调用是 Web 窗体设计器所必需的。
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

    End Sub
    Protected WithEvents txtUserID As System.Web.UI.WebControls.TextBox
    Protected WithEvents txtBookID As System.Web.UI.WebControls.TextBox
    Protected WithEvents ListDGrid As System.Web.UI.WebControls.DataGrid
    Protected WithEvents LendBtn As System.Web.UI.WebControls.LinkButton
    Protected WithEvents UserHolder As System.Web.UI.WebControls.PlaceHolder

    '注意: 以下占位符声明是 Web 窗体设计器所必需的。
    '不要删除或移动它。
    Private designerPlaceholderDeclaration As System.Object

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
        'CODEGEN: 此方法调用是 Web 窗体设计器所必需的
        '不要使用代码编辑器修改它。
        InitializeComponent()
    End Sub

#End Region

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        '在此处放置初始化页的用户代码
        If txtUserID.Text.ToString.Trim <> "" Then
            Dim obj As LoadUser = Me.LoadControl("LoadUser.ascx")
            If obj.LoadUserInfo(txtUserID.Text.ToString.Trim) = False Then
                Response.Write("<script>javascript:alert('该用户不存在或为非激活状态！！！');</script>")
            Else
                UserHolder.Controls.Clear()
                UserHolder.Controls.Add(obj)
            End If

        End If

    End Sub
    Private Sub BindDBGrid()
        Dim sqlstr As String = "select * from BookInfo,LendInfo where BookInfo.BookID=LendInfo.BookID and IsBack=0 and UserID='" + txtUserID.Text.ToString + "'"
        Dim obj As DBController = New DBController
        obj.BindDBGrd(sqlstr, ListDGrid)
    End Sub
    Private Function GetBookID() As String
        Dim sqlstr As String = "select BookID from BookInfo where BarCode='" + txtBookID.Text.ToString.Trim + "'"
        Dim BookID As String = ""
        Dim obj As DBController = New DBController
        Dim myreader As SqlDataReader = obj.ExecReaderSql(sqlstr)
        If myreader.Read Then
            BookID = myreader("BookID")
        End If
        obj.Close()
        Return BookID
    End Function

    Private Sub LendBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LendBtn.Click
        Dim str As String = ""
        Dim BookID As String = GetBookID()
        Dim obj As BookController = New BookController
        If obj.GetCurNum(txtUserID.Text) >= obj.GetMax(txtUserID.Text.ToString) Then
            Response.Write("<script>javascript:alert('借书数已满！！！');</script>")
            Return
        End If
        Dim state As Integer = obj.GetBookState(BookID)
        If state = 1 Then
            obj.LendBook(txtUserID.Text.ToString.Trim, BookID)
        ElseIf state = 0 And obj.IsUserBooking(txtUserID.Text.ToString.Trim, BookID) Then
            obj.LendBook(txtUserID.Text.ToString.Trim, BookID)
            obj.CancelBooking(txtUserID.Text.ToString.Trim, BookID)
        Else
            Select Case state
                Case -2 : Response.Write("<script>javascript:alert('此书不在流通状态或此书不存在！！！');</script>")
                Case -1 : Response.Write("<script>javascript:alert('此书不在书架上！！！');</script>")
                Case 0 : Response.Write("<script>javascript:alert('此书已经有人预约！！！');</script>")
            End Select
        End If
        BindDBGrid()
    End Sub

    Private Sub txtUserID_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtUserID.TextChanged

    End Sub
End Class