Know Dot Net Article

Add-ins - Enumerating Selected Controls

Get List of Controls Selected on a Form

by Les Smith

In an add-in, how do I get a list of the controls selected by the developer in the active forms designer?   I also would like to copy the selected controls to the clipboard.  Can I do that?  This article shows you how to do both of these functions.

I will use several objects from the System.ComponentModel namespace for the code in this article.  First, I create an instance of IDesignerHost interface.  This provides an interface for controlling components (controls) on the active forms designer from the add-in.   To see more documentation on the IDesignerHost interface click here.

Next, I will use the host object to create an ISelectionService interface to access the selection of controls.  The ISelectionService provides an interface for a forms designer to select components. To see more documentation on the ISelectionService, click here..  Assuming that the developer has selected at least one control, on the form, the code will create an array of the controls names, and finally copy the selected controls to the clipboard.

Figure 1 shows the skeleton of a Class that copies controls and code behind the controls to the clipboard.  This class is taken from NetCommander available at this site.  The method, CopySelectedControls, is designed to show you only how to enumerate and copy the controls.

Imports System.Windows.Forms
Imports EnvDTE
Imports Extensibility
Imports System.Text
Imports System.ComponentModel
Imports System.ComponentModel.Design

Public Class CCopyControlsAndCode
   Private oVB As EnvDTE.DTE ' applicationObject of the IDE
   Friend Function CopySelectedControls( _
      ByRef oFrm As frmCopyControlsAndCode) _
      As Boolean
      '` Copy code for all selected events.
      '` 1) Get list of the selected events by creating
      '' and using a IDesignerHost object.
      '' Copy the selected controls to the clipboard.
      Dim aComps() As String
      Dim j As Integer
      Dim IC As IComponent
      Dim c As Component
      Dim iCmpCount As Integer

      Try
         ' get a list of the selected components
         ' create an instance of the forms designer object
         Dim fdHost As IDesignerHost
         fdHost = CType(oVB.ActiveWindow.Object, IDesignerHost)

         ' get an ISelectionService interface to acces the selected controls
         Dim sel As ISelectionService
         sel = CType(fdHost.GetService(Type.GetType _
            ("System.ComponentModel.Design.ISelectionService,System")), _
               System.ComponentModel.Design.ISelectionService)

         If sel.GetSelectedComponents.Count = 0 Then
            MsgBox("No controls selected", vbExclamation)
            Exit Function
         End If

         Dim cmp As Component
         ReDim aComps(sel.GetSelectedComponents.Count - 1)

         ' build array of control names
         For Each cmp In sel.GetSelectedComponents
            aComps(i) = cmp.Site.Name
         Next

         ' aComps() now has the list of control names

         ' now destroy the designer object as we no
         ' longer need it.
         cmp = Nothing
         sel = Nothing
         fdHost = Nothing

         ' copy the controls to the clipboard
         oVB.ExecuteCommand("Edit.Copy")

         Return True
      Catch ex As System.Exception
         MsgBox(ex.ToString())
         Return False
      End Try
   End Function
End Class

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