VSTO Outlook Explorer BeforeMinimize，BeforeMaximize事件不会触发

Question

I spent the last hours figuring out how to subscribe to any Outlook explorer's BeforeMinimize and BeforeMaximize Events and failed. What I did so far:

public partial class ThisAddIn
{
    Outlook.Explorer explorer;
    Outlook.Application application;
    Outlook.ExplorerEvents_10_BeforeMinimizeEventHandler beforeMinimizeEventHandler;

    ThisAddin_Startup()
    {
        //... create custom Task pane

        application = Globals.ThisAddIn.Application;
        explorer = application.ActiveExplorer();
        beforeMinimizeEventHandler = new Outlook.ExplorerEvents_10_BeforeMinimizeEventHandler(explorer_BeforeMinimize);
        explorer.BeforeMinimize += beforeMinimizeEventHandler;

    }

    void explorer_BeforeMinimize(ref bool Cancel)
    {
        System.Windows.Forms.MessageBox.Show("BeforeMinimize");
        Cancel = true;
    }
}

The event never gets fired. I also tried other approaches like casting explorer to Outlook.ExplorerEvents_10_Event and then subscribing. I also checked that there is just one Explorer. Nothing works, though. Am I doing anything wrong? Thank you for your help.

Answer 1

Did a little modification with your code and I have found everything working now.

I have added Event Handler to Explorer.BeforeMinimize directly, instead of what you have added.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using Outlook = Microsoft.Office.Interop.Outlook;
using Office = Microsoft.Office.Core;

namespace OutlookAddIn4
{
    public partial class ThisAddIn
    {

        Outlook.Explorer explorer;
        Outlook.Application application;

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            application = Globals.ThisAddIn.Application;
            explorer = application.ActiveExplorer();
            explorer.BeforeMinimize += explorer_BeforeMinimize;
        }

        void explorer_BeforeMinimize(ref bool Cancel)
        {
            System.Windows.Forms.MessageBox.Show("BeforeMinimize");
            Cancel = true;
        }

        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
        }

        #region VSTO generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }

        #endregion
    }
}

After compilation, the startup code is compiled to

private void ThisAddIn_Startup(object sender, EventArgs e)
{
    this.application = Globals.ThisAddIn.Application;
    this.explorer = this.application.ActiveExplorer();
    (new ComAwareEventInfo(typeof(ExplorerEvents_10_Event), "BeforeMinimize")).AddEventHandler(this.explorer, new ExplorerEvents_10_BeforeMinimizeEventHandler(this.explorer_BeforeMinimize));
}