' taken from Tutorial04.vbproj
' Sometimes it is very useful to know the count of open COM Proxies in your application.
' NetOffice offers you a static property and notification event for this.

' LateBindingApi.Core.Factory.ProxyCount

' LateBindingApi.Core.Factory.ProxyCountChanged

' ' This example shows you how to use them. ' ' See chapter5 in technical documentation for further info. ' Dim _application As Excel.Application Public Sub New() ' This call is required by the Windows Form Designer. InitializeComponent() ' Initialize Api COMObject Support LateBindingApi.Core.Factory.Initialize() Dim changeHandler As Factory.ProxyCountChangedHandler = AddressOf Me.Factory_ProxyCountChanged AddHandler Factory.ProxyCountChanged, changeHandler End Sub Private Sub Factory_ProxyCountChanged(ByVal proxyCount As Integer) If (labelProxyCount.InvokeRequired) Then labelProxyCount.Tag = proxyCount.ToString() Dim updateHandler As MethodInvoker = AddressOf Me.UpdateLabel labelProxyCount.Invoke(updateHandler) Else labelProxyCount.Text = proxyCount.ToString() End If End Sub Private Sub buttonExcel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonExcel.Click If (IsNothing(_application)) Then ' start application _application = New Excel.Application() _application.DisplayAlerts = False buttonExcel.Text = "Quit Excel" buttonWorkbook.Enabled = True buttonAddins.Enabled = True buttonAddRemoveWorkbook.Enabled = True Else ' quit application _application.Quit() _application.Dispose() _application = Nothing buttonExcel.Text = "Start Excel" buttonWorkbook.Enabled = False buttonAddins.Enabled = False buttonAddRemoveWorkbook.Enabled = False End If End Sub Private Sub buttonWorkbook_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonWorkbook.Click ' 2 new proxies, the workbooks proxy(implicit) and the new workbook from Add() If (Not IsNothing(_application)) Then _application.Workbooks.Add() End If End Sub Private Sub buttonAddins_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonAddins.Click If (Not IsNothing(_application)) Then '1 new enumerator proxy and 1 new proxy for any Addin Dim item As Excel.AddIn For Each item In _application.AddIns Console.WriteLine(item.Name) Next item End If End Sub Private Sub buttonAddRemoveWorkbook_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonAddRemoveWorkbook.Click ' add a new worbook and a new worksheet to the workbook ' the worksheet is a child proxy from worbook, after dispose the workbook ' creates 4 new proxies ' the open proxy count is the same as before Dim proxyCount As Integer = LateBindingApi.Core.Factory.ProxyCount Dim book As Excel.Workbook = _application.Workbooks.Add() book.Worksheets.Add() Dim proxyCountAfterCreate As Integer = LateBindingApi.Core.Factory.ProxyCount 'dispose all child instances from application _application.DisposeChildInstances() Dim proxyCountAfterDispose As Integer = LateBindingApi.Core.Factory.ProxyCount Dim message As String = String.Format("Method creates a new Workbook with 1 new Worksheet" & vbNewLine & _ "ProxyCount before create is {0}" & vbNewLine & _ "ProxyCount after create is {1}" & vbNewLine & _ "ProxyCount after dispose Workbook is {2}", proxyCount, proxyCountAfterCreate, proxyCountAfterDispose) MessageBox.Show(message, Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Information) End Sub Private Sub UpdateLabel() labelProxyCount.Text = labelProxyCount.Tag End Sub

   See next: Tutorial05 - Understanding COMObject

Last edited Jul 20, 2011 at 12:24 AM by SebastianDotNet, version 4


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