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How to prevent a new toolbar button from being created everytime ...

Hi,

I'm coding a add-in for Outlook in C#. Below is a part of my code. It might be hard to read because of the limited width here but it's not that much code. Questions below:

private void ThisApplication_Startup(object sender, System.EventArgs e)
{
CreateButton();
}

private void CreateButton()
{
Office.CommandBars commandBars = this.ActiveExplorer().CommandBars;

// Create a toolbar button on the standard toolbar that calls ToolbarButton_Click when clicked
try
{
// See if it already exists
toolbarButton = (Office.CommandBarButton)commandBars["Standard"].Controls["ExportContacts"];
}
catch (Exception)
{
// Create it
toolbarButton = (Office.CommandBarButton)commandBars["Standard"].Controls.Add(1, System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value);
toolbarButton.Caption = "Export Contacts";
toolbarButton.TooltipText = "Export your contacts";
toolbarButton.FaceId = 2519;
toolbarButton.Style = Office.MsoButtonStyle.msoButtonIconAndCaption;
}

toolbarButton.Visible = true;
toolbarButton.Click += new Microsoft.Office.Core._CommandBarButtonEvents_ClickEventHandler(this.OnToolbarButtonClick);
}

As you see here all I do in ThisApplication_Startup is to call createButton which creates a toolbar button. My problem is that a new button is created everytime Outlook starts. I assume my try/catch-logic isn't doing what I want. Any ideas on how to make it check whether the button already exists before creating a new one?

Cheers
Magnus

ripern

Hi Magnus

It's not recommended to use try-catch for something that's not a true exception (error). While this worked OK in the old Visual Basic world, in the .NET world this will slow your application considerably. Plus, the way you've set this up, creating the toolbar will execute even if some other error occurs.

Are you certain that the line of code in the "try" block actually causes an error to occur? Might it not leave the toolbarButton variable = null? (no time to test it for you...)

It would probably be better to use the FindControl method of the CommandBars collection. Make sure you've assigned your control a unique TAG value, and check for the control using this (instead of ID, which is only for built-in controls).

-- Cindy Meister (Word MVP)

Cindy Meister

Thanks, I rewrote it entirely and thought I would post it here so others can look at it. It works like I wanted it to do. Something that could be improved though is to not create the button if it already exists but then it's click event didn't work instead so I delete it and then create it. I bit overhead but at least it works and probably only 0.5secs overhead or less. Maybe even better is to remove the button in ThisApplication_Shutdown(...), hmm.

private void ThisApplication_Startup(object sender, System.EventArgs e)
{
AddToolbarButton();
}

private void AddToolbarButton()
{
try
{
// Get a reference to the standard command bar
commandBarStandard = this.ActiveExplorer().CommandBars["Standard"];

// Check whether the "Export Contacts"-button already exists
Office.CommandBarButton foundButton = (Office.CommandBarButton)
this.ActiveExplorer().CommandBars["Standard"].
FindControl(Office.MsoControlType.msoControlButton,
System.Type.Missing, "Export Contacts", true, true);

// If the button exists we delete it (if we just leave it, it won't work like it should)
if (foundButton != null)
foundButton.Delete(true);

// Create the "Export Contacts"-button
buttonExportContacts = (Office.CommandBarButton)commandBarStandard.Controls.Add(1, missing, missing, missing, missing);
buttonExportContacts.Style = Office.MsoButtonStyle.msoButtonIconAndCaption;
buttonExportContacts.Caption = "Export Contacts";
buttonExportContacts.TooltipText = "Export your contacts to IA";
buttonExportContacts.Tag = "Export Contacts";
buttonExportContacts.FaceId = 2519;
buttonExportContacts.Click += new Office._CommandBarButtonEvents_ClickEventHandler(OnButtonClick);

commandBarStandard.Visible = true;
}
catch (ArgumentException e)
{
MessageBox.Show(e.Message);
}
}

ripern

<<Maybe even better is to remove the button in ThisApplication_Shutdown(...), hmm>>

Yes, if there's any chance the user would uninstall your Add-in :-)

-- Cindy Meister (Word MVP)

Cindy Meister

reply 4