判断一个窗体是否打开，我们可以用SysCmd的cSysCmdGetObjectState来进行判断，同样也可以用来对表、查询、报表进行判断,函数如下：

Function IsOpen(ObjName As String, ObjType As AcObjectType) As Boolean
  If SysCmd(acSysCmdGetObjectState, ObjType, ObjName) = 0 Then
     IsOpen = False
   Else
     IsOpen = True
  End If
End Function 


'-用法:  

If IsOpen("查询2", acQuery) Then
   MsgBox "查询2已打经打开"
  Else
   DoCmd.OpenQuery "查询2"
End If