[VB.NET]為控制項加上顯示載入動畫的機制

#End Region

Public Module ControlLoadingExtension

#Region “Class” Class LoadingInfo Private _loaddingBmp As Image Private _loaddingBmpActiveFrameIdx As Integer Private _loaddingBmpDimension As FrameDimension Private _loaddingBmpFrameCount As Integer Private _displayLocation As Point

    Property LoaddingBmp As Image
        Get
            Return _loaddingBmp
        End Get
        Set(ByVal value As Image)
            If _loaddingBmp IsNot value Then
                _loaddingBmp = value
                LoaddingBmpDimension = New FrameDimension(value.FrameDimensionsList(0))
                LoaddingBmpFrameCount = value.GetFrameCount(LoaddingBmpDimension)
                LoaddingBmpActiveFrameIdx = 0
            End If
        End Set
    End Property

    Property LoaddingBmpActiveFrameIdx As Integer
        Get
            Return _loaddingBmpActiveFrameIdx
        End Get
        Set(ByVal value As Integer)
            _loaddingBmpActiveFrameIdx = value
            LoaddingBmp.SelectActiveFrame(LoaddingBmpDimension, value)
        End Set
    End Property

    Property LoaddingBmpDimension As FrameDimension
        Get
            Return _loaddingBmpDimension
        End Get
        Private Set(ByVal value As FrameDimension)
            _loaddingBmpDimension = value
        End Set
    End Property

    Property LoaddingBmpFrameCount As Integer
        Get
            Return _loaddingBmpFrameCount
        End Get
        Private Set(ByVal value As Integer)
            _loaddingBmpFrameCount = value
        End Set
    End Property

    Property DisplayLocation As Point
        Get
            Return _displayLocation
        End Get
        Set(ByVal value As Point)
            _displayLocation = value
        End Set
    End Property
End Class

#End Region

#Region “Var” Private _loadingStatePool As HybridDictionary Private _updateThread As Thread #End Region

#Region “Private Property” Private ReadOnly Property m_LoadingStatePool() As HybridDictionary Get If _loadingStatePool Is Nothing Then _loadingStatePool = New HybridDictionary End If Return _loadingStatePool End Get End Property

Private Property m_UpdateThread As Thread
    Get
        If _updateThread Is Nothing Then
            _updateThread = New Thread(AddressOf ThreadingUpdatePhoto) With {.IsBackground = True}
        End If
        Return _updateThread
    End Get
    Set(ByVal value As Thread)
        _updateThread = value
    End Set
End Property

#End Region

#Region “Private Method” Private Sub InvalidLoaddingBmp(ByVal ctrl As Control) Dim info As LoadingInfo = DirectCast(m_LoadingStatePool(ctrl), LoadingInfo) ctrl.Invalidate(New Rectangle(info.DisplayLocation, info.LoaddingBmp.Size)) End Sub

Private Sub BindingControlEvent(ByVal ctrl As Control)
    UnBindingControlEvent(ctrl)
    AddHandler ctrl.Paint, AddressOf Control_Paint
    AddHandler ctrl.HandleDestroyed, AddressOf Control_HandleDestroyed
    AddHandler ctrl.Resize, AddressOf Control_Resize
End Sub

Private Sub UnBindingControlEvent(ByVal ctrl As Control)
    RemoveHandler ctrl.Paint, AddressOf Control_Paint
    RemoveHandler ctrl.HandleDestroyed, AddressOf Control_HandleDestroyed
    RemoveHandler ctrl.Resize, AddressOf Control_Resize
End Sub

Private Function GetDisplayLocation(ByVal ctrl As Control) As Point
    Dim info As LoadingInfo = DirectCast(m_LoadingStatePool(ctrl), LoadingInfo)
    Dim bmp As Bitmap = info.LoaddingBmp
    Return New Point(ctrl.Width \ 2 - bmp.Width \ 2, ctrl.Height \ 2 - bmp.Height \ 2)
End Function

Private Sub AdjustDisplayLocation(ByVal ctrl As Control)
    Dim info As LoadingInfo = DirectCast(m_LoadingStatePool(ctrl), LoadingInfo)
    Dim bmp As Bitmap = info.LoaddingBmp
    info.DisplayLocation = GetDisplayLocation(ctrl)
End Sub

Private Sub PaintGraphic(ByVal g As Graphics, ByVal ctrl As Control)
    Dim info As LoadingInfo = DirectCast(m_LoadingStatePool(ctrl), LoadingInfo)
    Dim bmp As Bitmap = info.LoaddingBmp
    info.LoaddingBmpActiveFrameIdx = (info.LoaddingBmpActiveFrameIdx + 1) Mod info.LoaddingBmpFrameCount
    g.DrawImage(bmp, info.DisplayLocation)
End Sub

Private Sub ThreadingUpdatePhoto()
    While True
        For idx As Integer = m_LoadingStatePool.Count - 1 To 0 Step -1
            InvalidLoaddingBmp(DirectCast(m_LoadingStatePool.Keys(idx), Control))
        Next
        Thread.Sleep(100)
    End While
End Sub

#End Region

#Region “Public Method” <Extension()> _ Function IsLoadingState(ByVal ctrl As Control) As Boolean Return m_LoadingStatePool.Contains(ctrl) End Function

<Extension()> _
Sub ActiveLoadingState(ByVal ctrl As Control, ByVal loaddingBmp As Image)
    If loaddingBmp Is Nothing Then
        Throw New ArgumentNullException("loaddingBmp")
    End If
    DeActiveLoadingState(ctrl)
    m_LoadingStatePool.Add(ctrl, New LoadingInfo() With {.LoaddingBmp = loaddingBmp})
    AdjustDisplayLocation(ctrl)
    BindingControlEvent(ctrl)
    If m_LoadingStatePool.Count = 1 Then
        m_UpdateThread.Start()
    End If
End Sub


<Extension()> _
Sub DeActiveLoadingState(ByVal ctrl As Control)
    If IsLoadingState(ctrl) Then
        UnBindingControlEvent(ctrl)
        m_LoadingStatePool.Remove(ctrl)
        ctrl.Invalidate()
    End If
    If m_LoadingStatePool.Count = 0 Then
        Try
            m_UpdateThread.Abort()
        Catch ex As Exception
        Finally
            m_UpdateThread = Nothing
        End Try
    End If
End Sub

#End Region

#Region “Event Process” Private Sub Control_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) PaintGraphic(e.Graphics, DirectCast(sender, Control)) End Sub

Private Sub Control_HandleDestroyed(ByVal sender As Object, ByVal e As EventArgs)
    DeActiveLoadingState(DirectCast(sender, Control))
End Sub

Private Sub Control_Resize(ByVal sender As Object, ByVal e As EventArgs)
    AdjustDisplayLocation(DirectCast(sender, Control))
End Sub

#End Region End Module

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    For Each c As Control In Me.Controls
        c.DeActiveLoadingState()
    Next
End Sub

End Class

• VB.NET