用vb打开cad已有图形的程序，老是报错“对象变量或with块变量未设置”,该怎么处理

用vb打开cad已有图形的程序，老是报错“对象变量或with块变量未设置”
刚开始学写cad与vb二次开发的程序就出问题了，请高人帮忙解决一下。

Dim acadapp As AcadApplication


Private Sub Command1_Click()
On Error Resume Next
Set acadapp = GetObject(, "AutoCAD.Application")
If Err Then
  Err.Clear
  Set acadapp = CreateObject("AutoCAD.Application")
  If Err Then
  MsgBox ("不能运行cad2006")
  Exit Sub
  End If
 End If
acadapp.Visible = True
End Sub

Private Sub Command2_Click()
Dim myfilename As String
myfilename = "D:\D1\资料\学习\小桥涵\佛赤路涵洞K14+010－双孔八字墙.dwg"
If Dir(myfilename) <> "" Then
acadapp.Documents.Open myfilename
Else
MsgBox "文件不存在"
End If
End Sub


[解决办法]
Dim acadapp As AcadApplication
改成
Dim acadapp As new AcadApplication
试试
[解决办法]

VB code

Private Sub Command2_Click()call Command1_Click()Dim myfilename As Stringmyfilename = "D:\D1\资料\学习\小桥涵\佛赤路涵洞K14+010－双孔八字墙.dwg"If Dir(myfilename) <> "" Thenacadapp.Documents.Open myfilenameElseMsgBox "文件不存在"End IfEnd Sub
[解决办法]
你的cad实例没有释放，虽然没有点保存，但是实例还在，自然是能正常运行的。