Question: I have a UI tool button, I would like to get and use the existing function (select elements tool) in Arcmap when I activate this button, does anybody know that how to call the existing function using Vb arcobjects ??

Answer: 
You can use the [ArcMap Commands](http://edndoc.esri.com/arcobjects/9.2/NET/858a508c-b771-467c-81e6-c6aa72d88f9c.htm), eg.

```
  Dim pUID As New UID
  Dim pCmdItem As ICommandItem
  ' Use the GUID of the Save command
  pUID.Value = "{161496AD-AC99-11D2-87F8-0000F8751720}"
  ' or you can use the ProgID
  ' pUID.Value = "esriArcMapUI.EditSelectAllCommand"
  pUID.SubType = 3
  Set pCmdItem = Application.Document.CommandBars.Find(pUID)
  pCmdItem.Execute

```

Or, check out this forum post to grab elements on mouse up event.

<http://forums.esri.com/Thread.asp?c=93&f=993&t=158293>
Not sure if I understand you correctly, but would it not make sense to explicitly GET the tool you want...just in case the user has not selected it? It's OK to set it if it's already set.

```
Dim pCmdBar As ICommandBar
Dim pCmdItem As ICommandItem
Dim pUID As New UID

Set pCmdItem = Document.Parent.Document.CommandBars.Find(ArcID.PageLayout_SelectTool)
Set ThisDocument.Parent.CurrentTool = pCmdItem

```

Note that ArcID.PageLayout\_SelectTool is for ArcGIS 10, in 9.3 it was Select\_Elements I think.

Hope this helped.