create design time controls with smart tag

Question

Ok I have been working on this idea of a control that I have. I want the control to be able to add other controls to the form that it is on at design time. I am having a hell of a time trying to figure this out. I decided if nothing else I will just serialize to the code behind file myself. The only issue is I can't seem to get the location of the code behind file. I have only been able to get the location of the solution. I want to at least get the directory of the project before I go reading the files to see if it is the correct one. Anyways here is my code if there is another better way to do this.

<Designer(GetType(PanelManagerControlDesigner))> _
Public Class DynamicViewControl
    Inherits System.Windows.Forms.Panel
End Class

Public Class PanelManagerControlDesigner
    Inherits System.Windows.Forms.Design.ControlDesigner

    Public _Control As DynamicViewControl

    Public Overrides Sub Initialize(ByVal component As System.ComponentModel.IComponent)
        MyBase.Initialize(component)
        _Control = Me.Control
    End Sub

    Public Overrides ReadOnly Property ActionLists() As System.ComponentModel.Design.DesignerActionListCollection
        Get
            Dim d As New System.ComponentModel.Design.DesignerActionListCollection()
            d.Add(New PanelManagerControlDesignerActionList(Me))
            Return d
        End Get
    End Property

End Class

Public Class PanelManagerControlDesignerActionList
    Inherits System.ComponentModel.Design.DesignerActionList

    Dim _controlDesigner As PanelManagerControlDesigner
    Dim _designerActionUISvc As System.ComponentModel.Design.DesignerActionUIService
    Dim _Control As DynamicViewControl

    Public Sub New(ByVal designer As PanelManagerControlDesigner)
        MyBase.New(designer.Component)
        _designerActionUISvc = GetService(GetType(System.ComponentModel.Design.DesignerActionUIService))
        _controlDesigner = designer
        _Control = designer._Control
    End Sub

    Private Sub AddPanel()
        Dim p As New Panel()
        Dim i As Integer = 0
        '*****I NEED TO WRITE TO THE CODE BEHIND FILE RIGHT HERE********
    End Sub

    Public Overrides Function GetSortedActionItems() As System.ComponentModel.Design.DesignerActionItemCollection
        Dim items As New System.ComponentModel.Design.DesignerActionItemCollection()
        Dim mi As New System.ComponentModel.Design.DesignerActionMethodItem(Me, "AddPanel", "Add Panel", "Methods")
        items.Add(mi)
        Return items
    End Function
End Class