Module InvokeRequiredHandler
    <System.Runtime.CompilerServices.Extension()> _
    Public Sub HandleInvokeRequired(Of T As ISynchronizeInvoke)(ByVal controlToInvoke As T, ByVal actionToPerform As Action(Of T))
        'Check to see if the control's InvokeRequired property is true
        If controlToInvoke.InvokeRequired Then
            'Use Invoke() to invoke your action
            controlToInvoke.Invoke(actionToPerform, New Object() {controlToInvoke})
        Else
            'Perform the action
            actionToPerform(controlToInvoke)
        End If
    End Sub
End Module

HandleInvokeRequired(Textbox1, ¿?)