求解释代码意思
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 Not IsPostBack Then
BindData()
End If
End Sub
Private Sub BindData()
Dim obj As DBController = New DBController
obj.BindListBox("select * from BookInfo order by BookID asc", BookList)
obj.Close()
End Sub

Private Sub BookList_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles BookList.SelectedIndexChanged
Dim BookID As String = BookList.SelectedValue.ToString.Trim
Dim sqlstr As String = "select * from BookInfo where BookID =" + BookID
Dim obj As DBController = New DBController
obj.Open()
Dim myreader As SqlDataReader = obj.ExecReaderSql(sqlstr)
If myreader.Read Then
txtBookName.Text = myreader("BookName")
txtPubName.Text = myreader("PubName")
txtBookAuthor.Text = myreader("BookAuthor")
DpStyle.SelectedValue = myreader("BookStyle")
txtUploadDate.Text = myreader("UploadDate")
txtPubDate.Text = myreader("PubDate")
txtSeries.Text = myreader("Series")
txtSubject.Text = myreader("Subject")
DpLanguage.SelectedValue = myreader("Language")
txtISBN.Text = myreader("ISBN")
txtSearchNO.Text = myreader("SearchNO")
DpBookState.SelectedValue = myreader("BookState")
txtPrice.Text = myreader("Price")
txtBarCode.Text = myreader("BarCode")
End If
obj.Close()

[解决办法]

VB.NET code

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 Not IsPostBack Then  BindData()'首次加载时绑定数据  End If  End Sub  Private Sub BindData()’绑定BookList对象的方法  Dim obj As DBController = New DBController  obj.BindListBox("select * from BookInfo order by BookID asc", BookList)  obj.Close()  End Sub  Private Sub BookList_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles BookList.SelectedIndexChanged  Dim BookID As String = BookList.SelectedValue.ToString.Trim'取选中项的值  Dim sqlstr As String = "select * from BookInfo where BookID =" + BookID'根据取值拼结sql字符串  Dim obj As DBController = New DBController  obj.Open()  Dim myreader As SqlDataReader = obj.ExecReaderSql(sqlstr)  If myreader.Read Then'取出记录集，若存在，则对下面的一系列控件赋值  txtBookName.Text = myreader("BookName")  txtPubName.Text = myreader("PubName")  txtBookAuthor.Text = myreader("BookAuthor")  DpStyle.SelectedValue = myreader("BookStyle")  txtUploadDate.Text = myreader("UploadDate")  txtPubDate.Text = myreader("PubDate")  txtSeries.Text = myreader("Series")  txtSubject.Text = myreader("Subject")  DpLanguage.SelectedValue = myreader("Language")  txtISBN.Text = myreader("ISBN")  txtSearchNO.Text = myreader("SearchNO")  DpBookState.SelectedValue = myreader("BookState")  txtPrice.Text = myreader("Price")  txtBarCode.Text = myreader("BarCode")  End If  obj.Close()'关闭数据库对象