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Vb.net &引用;对象引用未设置为对象的实例;正在尝试添加到列表中_Vb.net - Fatal编程技术网

Vb.net &引用;对象引用未设置为对象的实例;正在尝试添加到列表中

Vb.net &引用;对象引用未设置为对象的实例;正在尝试添加到列表中,vb.net,Vb.net,我创建了一个对象“email”列表,其中包含“email”对象,该对象有3个参数(字符串地址、字符串主题、字符串正文) 然后我想通过创建更多的“电子邮件”实例来添加到列表中。然而,我尝试了很多不同的方法,但都没有成功 Public Class Test Public emails As List(Of Email) Private Sub Test_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) H

我创建了一个对象“email”列表,其中包含“email”对象,该对象有3个参数(字符串地址、字符串主题、字符串正文)

然后我想通过创建更多的“电子邮件”实例来添加到列表中。然而,我尝试了很多不同的方法,但都没有成功

Public Class Test

   Public emails As List(Of Email)

   Private Sub Test_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

      emails(0).setAddress("Hello")
      emails(0).setSubject("World2")
      emails(0).setBody("Why don't you work?")
      emails.Add(New Email("Hello2", "World2", "Why don't you work?2"))

   End Sub

   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
       Label1.Text = emails(0).getAddress
       Label2.Text = emails(0).getSubject
       Label3.Text = emails(0).getBody

       Label4.Text = emails(1).getAddress
       Label5.Text = emails(1).getSubject
       Label6.Text = emails(1).getBody
   End Sub
End Class
如果单击按钮1,则会出现错误“对象引用未设置为对象的实例”


谢谢。

您没有创建列表的实例,您只是声明了它

 Public emails As New List(Of Email) 
 '                ^^^