Visual Basic:未将对象引用设置为对象的实例 [英] visual basic: object reference not set to an instance of an object

问题描述

我观看了一个视频教程，看到这个人编写并执行下面的代码并工作，但是当我尝试编译我的代码时，它说对象引用未设置为对象的实例".我已经尝试了几件事，看看我是否能找到问题所在，但无济于事.

i watched a video tutorial and saw the guy write and execute the code below and worked but when i try to compile mine it says "object reference not set to an instance of an object". i have tried several things to see if i can get what the problem is but to no avail.

Imports System.IO
Public Class Form2

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            Dim myline = New StreamReader("TextFile1.txt")
            Dim line As String = ""
            While Not IsNothing(line)
                line = myline.ReadLine
                If IsNothing(line) Then
                    TextBox2.AppendText(line)
                End If
            End While
            myline.Close()

        Catch ex As Exception

            TextBox2.AppendText(ex.Message)
            MsgBox(ex.Message)

        End Try


    End Sub

End Class

有人可以帮忙吗?谢谢

推荐答案

我认为您缺少一个不是:

            If Not IsNothing(line) Then
                TextBox2.AppendText(line)
            End If

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