Hi,

I'm developing an Office COM Add-in by using Visual C# .NET.

The purpose of the add-in is to prevent any open workbook to get closed.
To achieve this I've implemented the following handler for the
Workbook_BeforeClose event of the Excel.Application object.

private void Connect_WorkbookBeforeClose(Excel.Workbook Wb, ref bool Cancel)
{
System.Windows.Forms.MessageBox.Show("It's not allowed closing the
workbook!");
Cancel = true;
}

At runtime, closing a workbook it pops up the message AND CLOSES the
workbook. The even is not canceled.

Am I missing anything?

Thanks,
Mircea

Hi

It seems that I can not reproduce the problem.
Here is my whole test code your reference.
If you still have any problem, I think you may try to run it on another
machine to see if that works.
namespace ExcelAddin1
{
using System;
using Microsoft.Office.Core;
using Extensibility;
using System.Runtime.InteropServices;
using Excel = Microsoft.Office.Interop.Excel;
using System.Diagnostics;

#region Read me for Add-in installation and setup information.
// When run, the Add-in wizard prepared the registry for the Add-in.
// At a later time, if the Add-in becomes unavailable for reasons such as:
// 1) You moved this project to a computer other than which is was
originally created on.
// 2) You chose 'Yes' when presented with a message asking if you wish
to remove the Add-in.
// 3) Registry corruption.
// you will need to re-register the Add-in by building the MyAddin21Setup
project
// by right clicking the project in the Solution Explorer, then choosing
install.
#endregion

/// <summary
/// The object for implementing an Add-in.
/// </summary
/// <seealso class='IDTExtensibility2' /
[GuidAttribute("BE133DE0-82CE-4EBB-AA88-517A54FCBC3F"),
ProgId("ExcelAddin1.Connect")]
public class Connect : Object, Extensibility.IDTExtensibility2
{
/// <summary
/// Implements the constructor for the Add-in object.
/// Place your initialization code within this method.
/// </summary
public Connect()
{
}

/// <summary
/// Implements the OnConnection method of the IDTExtensibility2
interface.
/// Receives notification that the Add-in is being loaded.
/// </summary
/// <param term='application'
/// Root object of the host application.
/// </param
/// <param term='connectMode'
/// Describes how the Add-in is being loaded.
/// </param
/// <param term='addInInst'
/// Object representing this Add-in.
/// </param
/// <seealso class='IDTExtensibility2' /
public void OnConnection(object application,
Extensibility.ext_ConnectMode connectMode, object addInInst, ref
System.Array custom)
{
exApp = application as Excel.Application;
exApp.WorkbookBeforeClose+=new
Microsoft.Office.Interop.Excel.AppEvents_WorkbookB eforeCloseEventHandler(exA
pp_WorkbookBeforeClose);
}

/// <summary
/// Implements the OnDisconnection method of the IDTExtensibility2
interface.
/// Receives notification that the Add-in is being unloaded.
/// </summary
/// <param term='disconnectMode'
/// Describes how the Add-in is being unloaded.
/// </param
/// <param term='custom'
/// Array of parameters that are host application specific.
/// </param
/// <seealso class='IDTExtensibility2' /
public void OnDisconnection(Extensibility.ext_DisconnectMode
disconnectMode, ref System.Array custom)
{
}

/// <summary
/// Implements the OnAddInsUpdate method of the IDTExtensibility2
interface.
/// Receives notification that the collection of Add-ins has changed.
/// </summary
/// <param term='custom'
/// Array of parameters that are host application specific.
/// </param
/// <seealso class='IDTExtensibility2' /
public void OnAddInsUpdate(ref System.Array custom)
{
}

/// <summary
/// Implements the OnStartupComplete method of the IDTExtensibility2
interface.
/// Receives notification that the host application has completed
loading.
/// </summary
/// <param term='custom'
/// Array of parameters that are host application specific.
/// </param
/// <seealso class='IDTExtensibility2' /
public void OnStartupComplete(ref System.Array custom)
{
}

/// <summary
/// Implements the OnBeginShutdown method of the IDTExtensibility2
interface.
/// Receives notification that the host application is being
unloaded.
/// </summary
/// <param term='custom'
/// Array of parameters that are host application specific.
/// </param
/// <seealso class='IDTExtensibility2' /
public void OnBeginShutdown(ref System.Array custom)
{
}
private Excel.Application exApp=null;

private void
exApp_WorkbookBeforeClose(Microsoft.Office.Interop .Excel.Workbook Wb, ref
bool Cancel)
{
Debug.WriteLine("Before close");
System.Windows.Forms.MessageBox.Show("Before close");
Cancel = true;
}
}
}

Best regards,

Peter Huang
Microsoft Online Partner Support

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