“对象引用未设置为对象的实例”尝试添加到列表

Question

我创建了包含具有3个参数的“email”对象的对象“emails”列表（String Address，String Subject，String Body）

然后我想通过创建更多的“email”实例来添加到列表中。但是，我尝试了很多不同的方式，而且没有。

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 

如果我点击button1，我得到错误“对象引用未设置为对象的实例”。

谢谢。

Answer 1

您尚未创建列表的实例，只声明了它。

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