System.NullReferenceException出错，请问是什么原因？如何解决？谢谢！

[xoceco]

'申明一个类
Public Class Class_DBLink
Private m_name, m_dbtype, m_database As String
Public Property Name() As String
Get
Return m_name
End Get
Set(ByVal value As String)
m_name = value
End Set
End Property

Public Property DatabaseType() As String
Get
Return m_dbtype
End Get
Set(ByVal value As String)
m_dbtype = value
End Set
End Property

Public Property Database() As String
Get
Return m_database
End Get
Set(ByVal value As String)
m_database = value
End Set
End Property
End Class

'读取ini文件代码
Module ModuleMain
'引用ini文件读写函数
Public Declare Function GetPrivateProfileString Lib "kernel32" Alias "GetPrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As String, ByVal lpDefault As String, ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
Public Declare Function WritePrivateProfileString Lib "kernel32" Alias "WritePrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As String, ByVal lpString As String) As Boolean
Public DBLinkCount As Integer '数据连接总数
Public DBLink() As Class_DBLink '申明数据连接类的实例


Public Sub GetAppSetting() '读取ini文件设置值
Dim Result As String
Dim i, LCount As Integer
On Error GoTo Err

'=======================================
Result = Space$(256)
GetPrivateProfileString("数据源", "总数", "1", Result, 255, Application.StartupPath & "\DBLink.ini")
Result = Trim(Result)
LCount = Result

For i = 1 To LCount '依次读取所有数据连接
If i = 1 Then '第１个数据源
ReDim DBLink(1)
Else
ReDim Preserve DBLink(i)
End If
Result = Space$(256)
GetPrivateProfileString(i, "Name", "数据源" & i.ToString, Result, 255, Application.StartupPath & "\DBLink.ini")
Result = Trim(Result.ToString)
DBLink(1).Name = Result.ToString '运行到这里时出错：System.NullReferenceException
Next

Exit Sub
Err:
MsgBox(Err.Description)

End Sub

End Module

[wuyq11]

DBLink(1)是否为 null.没有实例化

[xoceco]

不好意思，我是新手，应该如何实例化？

[十八道胡同]

这个时候 DBLink中的元素有几个？
DBLink(0).Name

[HarveyYan]

定义数组的时候初始化容量：
Public DBLink(255) As Class_DBLink

[xoceco]

按照:
Public DBLink(1) As Class_DBLink
后：
DBLink(１).Name = Result.ToString 这里还是同样出错啊！

[HarveyYan]

像这样试试

Result = Trim(Result.ToString)
DBLink(1)=new Class_DBLink
DBLink(1).Name = Result.ToString

[xoceco]

谢谢edward8819
按照你的方法，可以了！
那是不是数组里每一个元素都得new一下？

[HarveyYan]

别客气啊。是这样的，对像要实例化才能使用。

[Quote=引用 9 楼 xoceco 的回复:]
谢谢edward8819
按照你的方法，可以了！
那是不是数组里每一个元素都得new一下？
[/Quote]

[silentwins]

设置个断电调试一下不就知道为什么会为空了？！

[silentwins]

断点