Demetrio Cassarino
120 lines
3.5 KiB
VB.net
120 lines
3.5 KiB
VB.net
'/******************************************************************************
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'* *
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'* PROJECT : EOS Digital Software Development Kit EDSDK *
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'* NAME : Observer.vb *
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'* *
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'* Description: This is the Sample code to show the usage of EDSDK. *
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'* *
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'* *
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'*******************************************************************************
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'* *
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'* Written and developed by Camera Design Dept.53 *
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'* Copyright Canon Inc. 2006 All Rights Reserved *
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'* *
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'*******************************************************************************
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'* File Update Information: *
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'* DATE Identify Comment *
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'* ----------------------------------------------------------------------- *
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'* 06-03-22 F-001 create first version. *
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'* *
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'******************************************************************************/
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Option Explicit On
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Imports System
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Imports System.Runtime.InteropServices
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Public Interface Observer
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Sub update(ByVal from As Observable, ByVal msg As Integer, ByVal data As Integer)
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End Interface
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Public Class Observable
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Private m_numof_ob As Integer
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Private m_observers() As Observer
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Public Sub New()
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m_numof_ob = -1 ' ArraySize = 0
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End Sub
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Protected Overrides Sub Finalize()
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deleteObservers()
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End Sub
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'// Add an observer.
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Public Sub addObserver(ByVal ob As Object)
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m_numof_ob = m_numof_ob + 1
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ReDim Preserve m_observers(m_numof_ob)
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m_observers(m_numof_ob) = ob
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End Sub
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'// Delete an observer .
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Public Sub deleteObserver(ByVal ob As Observer)
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Dim iCnt As Integer
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If m_numof_ob <= 0 Then
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ReDim m_observers(-1)
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m_numof_ob = -1
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Else
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For iCnt = 0 To m_numof_ob
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If m_observers(iCnt) Is ob Then
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Do
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m_observers(iCnt) = m_observers(iCnt + 1)
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iCnt = iCnt + 1
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Loop Until iCnt = m_numof_ob
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End If
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Next
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m_observers(m_numof_ob) = Nothing
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m_numof_ob = m_numof_ob - 1
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ReDim Preserve m_observers(m_numof_ob)
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End If
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End Sub
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'// Notify to observers.
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Public Sub notifyObservers(ByVal msg As Integer, Optional ByVal data As Integer = 0)
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Exit Sub
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Dim iCnt As Integer
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For iCnt = m_numof_ob To 0 Step -1
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m_observers(iCnt).update(Me, msg, data)
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iCnt = iCnt - 1
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Next
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End Sub
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Public Sub deleteObservers()
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Dim icnt As Integer
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For icnt = 0 To m_numof_ob
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m_observers(icnt) = Nothing
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Next
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' Set the number of observer as 0.
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m_numof_ob = 0
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End Sub
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Public Function countObservers() As Integer
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Return m_numof_ob
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End Function
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End Class
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