Question

我有一个转发器，可以加载一些东西。我还有一个按钮，它有一个SQL命令来删除转发器的所有内容，但不幸的是，当用户按下“删除”按钮后页面重新加载时，这些项目仍然存在。

我为页面加载子尝试了类似的东西：

   Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
            If IsPostBack Then
                bookShelfContainer.DataSource = Nothing
                Exit Sub
            End If
displayUserBooks()
    End Sub

这是转发器的子设备：

 Sub displayUserBooks()
        Dim conn As New OleDb.OleDbConnection(ConfigurationManager.ConnectionStrings("BookMeetConnString").ConnectionString)
        Dim cmd As OleDbCommand = New OleDbCommand()
        cmd.Connection = conn
        conn.Open()
        Session("currentuser") = User.Identity.Name
        cmd.Parameters.AddWithValue("@currentUser", Session("currentuser"))
        cmd.CommandText = String.Format("SELECT TOP 6 booklist.ID, booklist.Title, booklist.Author, booklist.imgurl, bookshelfjunction.BookID FROM booklist INNER JOIN bookshelfjunction ON bookshelfjunction.BookID = booklist.ID WHERE bookshelfjunction.UserName = @currentUser")
        bookShelfContainer.DataSource = cmd.ExecuteReader()
        bookShelfContainer.DataBind()
        conn.Close()
    End Sub

删除功能以防万一你需要它：

Protected Sub btnClearBookshelf()
        Dim conn As New OleDb.OleDbConnection(ConfigurationManager.ConnectionStrings("BookMeetConnString").ConnectionString)
        Dim cmd As OleDbCommand = New OleDbCommand()
        cmd.Connection = conn
        conn.Open()
        Session("currentuser") = User.Identity.Name
        cmd.Parameters.AddWithValue("@currentUser", Session("currentuser"))
        cmd.CommandText = String.Format("DELETE FROM bookshelfjunction WHERE bookshelfjunction.UserName = @currentUser")
        cmd.ExecuteNonQuery()
        conn.Close()
    End Sub

我需要在Page_Load If IsPostBack评估中写什么来确保转发器数据库？

Answer 1

您没有看到更新，因为您只是在数据库中创建它们，而不是在Repeater控件的数据集中。它保留了您绑定的DataSet，并且您没有使用新数据刷新它。

Protected Sub btnClearBookshelf()
    Dim conn As New OleDb.OleDbConnection(ConfigurationManager.ConnectionStrings("BookMeetConnString").ConnectionString)
    Dim cmd As OleDbCommand = New OleDbCommand()
    cmd.Connection = conn
    conn.Open()
    Session("currentuser") = User.Identity.Name
    cmd.Parameters.AddWithValue("@currentUser", Session("currentuser"))
    cmd.CommandText = String.Format("DELETE FROM bookshelfjunction WHERE bookshelfjunction.UserName = @currentUser")
    cmd.ExecuteNonQuery()
    conn.Close()

    displayUserBooks()

End Sub

因此，您需要重新获取数据以使您的应用知道更新，然后将新数据集绑定到Repeater以显示新数据。如果您认为由于您的事件而发生这种情况，请记住事件处理程序在Page_Load之后运行。

在回发后更新ASP.NET转发器数据

1 个答案: