Question

这里我在类文件account.vb中声明了getdata method（）。点击GET按钮作为输出后，它会将msgbox显示为0 0 ....所以请帮助我：

Default.aspx.vb

Partial Class _Default
    Inherits System.Web.UI.Page

    'declaring the obj of class account

    Dim obj As New account



    Protected Sub btn_create_Click(sender As Object, e As System.EventArgs) Handles btn_create.Click

        'initializing the object obj on class accounts
        obj = New account



    End Sub


    Protected Sub btn_set_Click(sender As Object, e As System.EventArgs) Handles btn_set.Click

        'sending the values from textboxes to accounts class through method setdata



        Try
            obj.setdata(CInt(txt_accno.Text), (txt_name.Text), CInt(txt_bal.Text))

            'obj.setdata(txt_accno.Text, txt_name.Text, txt_bal.Text)

            MsgBox("value are set")

        Catch ex As Exception

            MsgBox(ex.Message)
        End Try


    End Sub

    Protected Sub btn_get_Click(sender As Object, e As System.EventArgs) Handles btn_get.Click

        'calling the method getdata to view the output


        Try

            obj.getdata()

        Catch ex As Exception

            MsgBox(ex.Message)
        End Try

    End Sub

End Class

Account.vb

Imports Microsoft.VisualBasic

Public Class account

    Private accno As Integer
    Private acc_name As String
    Private bal As Integer


    'public method to populate above three private variable

    Public Sub setdata(ByVal a As Integer, ByVal b As String, ByVal c As Integer)
        Me.accno = a
        Me.acc_name = b
        Me.bal = c
    End Sub

    Public Sub getdata()
        MsgBox(Me.accno.ToString + vbNewLine + Me.acc_name + vbNewLine + Me.bal.ToString)
    End Sub

    End Class

Answer 1

您正在尝试在页面中使用Obj。无论何时单击按钮，Obj可以重置为回发。您需要存储Obj的值。有很多方法可以存储它。 ASP.NET会话状态使您能够在用户在Web应用程序中导航ASP.NET页面时存储和检索用户的值。 HTTP是无状态协议。这意味着Web服务器将页面的每个HTTP请求视为独立请求。服务器不保留先前请求期间使用的变量值的知识。 ASP.NET会话状态在有限时间窗口内将来自同一浏览器的请求标识为会话，并提供了在该会话期间持久保存变量值的方法。默认情况下，为所有ASP.NET应用程序启用ASP.NET会话状态。

因此使用会话Obj对象保留，当您设置和获取数据时，即使回发发生，它仍保留在页面上

尝试以下代码

Default.aspx.vb

Partial Class _Default
    Inherits System.Web.UI.Page

    'declaring the obj of class account

    Dim obj As New account



    Protected Sub btn_create_Click(sender As Object, e As System.EventArgs) Handles btn_create.Click

        'initializing the object obj on class accounts
        obj = New account

        session("ClsObj") = obj

    End Sub


    Protected Sub btn_set_Click(sender As Object, e As System.EventArgs) Handles btn_set.Click

        'sending the values from textboxes to accounts class through method setdata



        Try
            obj = session("ClsObj")
            obj.setdata(CInt(txt_accno.Text), (txt_name.Text), CInt(txt_bal.Text))

            'obj.setdata(txt_accno.Text, txt_name.Text, txt_bal.Text)

            MsgBox("value are set")

        Catch ex As Exception

            MsgBox(ex.Message)
        End Try


    End Sub

    Protected Sub btn_get_Click(sender As Object, e As System.EventArgs) Handles btn_get.Click

        'calling the method getdata to view the output


        Try
            obj = session("ClsObj")
            obj.getdata()

        Catch ex As Exception

            MsgBox(ex.Message)
        End Try

    End Sub

End Class

*************************************************
Account.vb

Imports Microsoft.VisualBasic

Public Class account

    Private accno As Integer
    Private acc_name As String
    Private bal As Integer


    'public method to populate above three private variable

    Public Sub setdata(ByVal a As Integer, ByVal b As String, ByVal c As Integer)
        Me.accno = a
        Me.acc_name = b
        Me.bal = c
    End Sub

    Public Sub getdata()
        MsgBox(Me.accno.ToString + vbNewLine + Me.acc_name + vbNewLine + Me.bal.ToString)
    End Sub

    End Class

Answer 2

试试这个：

Protected Sub btn_create_Click(sender As Object, e As System.EventArgs) Handles btn_create.Click
    Dim obj As New account
    obj = New account
    Session["obj"] = obj
End Sub

Protected Sub btn_set_Click(sender As Object, e As System.EventArgs) Handles btn_set.Click
    Try
        Dim obj  as New account
        obj = CType(Session["obj"], account)
        obj.setdata(CInt(txt_accno.Text), (txt_name.Text), CInt(txt_bal.Text))
        MsgBox("value are set")
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End Sub

Protected Sub btn_get_Click(sender As Object, e As System.EventArgs) Handles btn_get.Click
    Try
        Dim obj  as New account
        obj = CType(Session["obj"], account)
        obj.getdata()
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End Sub

类文件中的getdata方法不显示输出

2 个答案: