setting objects to nothing

[vbgladiator]

Hey,

If I have an object, how can I set it to nothing?
I want to be able to check with is nothing.
Calling the dispose method doesn't set the object to nothing. I want the object to be in the same state as when I was declared.

Thanks,

[RobDog888]

Depending on the object you can do a .Close that also calls the .Dispose method.
Also, actually setting the object equal to nothing works too. oApp = Nothing.

Finally you can call a garbage collection with GC.Collect().

[Mr.No]

This is how I personally handle connection objects

Private Sub QueryDB()
[INDENT]
Dim oConn as SqlConnection
 
Try
 
    oConn = new SqlConnection("connection string")
    oConn.Open()
   ' execute query
 
Catch ex as Exception
 
Finally
   If Not (oConn is Nothing) Then
      With oConn
         If .State <> StateClosed Then
            .Close()
         End If
      End With
       oConn = Nothing
     
End If
 
End Try
[/INDENT]
 
End Sub

[jmcilhinney]

You don't set objects to Nothing. An object is something, not Nothing. You can set a variable to Nothing, so instead of referring to an object, which is something, it will refer to Nothing:

myVar = Nothing

Note that this does not affect the object though. If an object has a Dispose method then you should call it when you have finished with the object. Setting a variable to Nothing generally has no useful effect, although there are some cases where it does. If your variable will lose scope immediately or almost immediately anyway then it is pointless.

[RobDog888]

Yes, but you know we have this discussion allot but an Object can be set to Nothing. It just reinforces the Disposal of the object if it hasnt gone out of scope

[wossname]

Also if you have a load o references all pointing to the same object then setting one of those references to nothing will not affect either the object or the other references.

[kleinma]

This is how I personally handle connection objects

Private Sub QueryDB()
[INDENT]
Dim oConn as SqlConnection
 
Try
 
    oConn = new SqlConnection("connection string")
    oConn.Open()
   ' execute query
 
Catch ex as Exception
 
Finally
   If Not (oConn is Nothing) Then
      With oConn
         If .State <> StateClosed Then
            .Close()
         End If
      End With
       oConn = Nothing
     
End If
 
End Try
[/INDENT]
 
End Sub

You never actually dispose in that cleanup...

Finally
   If Not (oConn is Nothing) Then
      With oConn
         If .State <> StateClosed Then
            .Close()
         End If
         .Dispose
      End With
      oConn = Nothing
    End If